Add cash ledger event-source breakdown and reconciliation API/UI (3d-31 B4c)

9 files changed, 997 insertions, 2 deletions

diff --git a/src/FundLab.Api/App.fs b/src/FundLab.Api/App.fs
index d5c3a50..3d89dae 100644
--- a/src/FundLab.Api/App.fs
+++ b/src/FundLab.Api/App.fs
@@ -487,6 +487,35 @@ type CapitalDepositResponse =
         createdAt: string
     }
 
+type CashLedgerEventResponse =
+    {
+        source: string
+        eventDate: string
+        amount: string
+        referenceType: string
+        referenceId: string
+        note: string option
+    }
+
+type CashLedgerSourceResponse =
+    {
+        source: string
+        netAmount: string
+        eventCount: int
+    }
+
+type CashReconciliationResponse =
+    {
+        fundId: Guid
+        openingCash: string
+        netInflow: string
+        closingCash: string
+        ledgerBalance: string
+        difference: string
+        sources: CashLedgerSourceResponse list
+        events: CashLedgerEventResponse list
+    }
+
 type FundReturnsPointResponse =
     {
         date: string
@@ -846,6 +875,39 @@ module App =
             createdAt = timestampText deposit.CreatedAt
         }
 
+    let private cashLedgerEventResponse (event: CashLedger.CashLedgerEvent) : CashLedgerEventResponse =
+        {
+            source = CashLedger.sourceText event.Source
+            eventDate = dateText event.EventDate
+            amount = cashText event.Amount
+            referenceType = event.ReferenceType
+            referenceId = event.ReferenceId
+            note = event.Note
+        }
+
+    let private cashReconciliationResponse
+        (fundId: Guid)
+        (reconciliation: CashLedger.CashReconciliation)
+        (events: CashLedger.CashLedgerEvent list)
+        : CashReconciliationResponse =
+        {
+            fundId = fundId
+            openingCash = cashText reconciliation.OpeningCash
+            netInflow = cashText reconciliation.NetInflow
+            closingCash = cashText reconciliation.ClosingCash
+            ledgerBalance = cashText reconciliation.LedgerBalance
+            difference = cashText reconciliation.Difference
+            sources =
+                reconciliation.Sources
+                |> List.map (fun total ->
+                    {
+                        source = CashLedger.sourceText total.Source
+                        netAmount = cashText total.NetAmount
+                        eventCount = total.EventCount
+                    })
+            events = events |> List.map cashLedgerEventResponse
+        }
+
     let private sipPlanResponse (plan: SipPlanRecord) : SipPlanResponse =
         {
             id = plan.Id
@@ -1763,6 +1825,20 @@ module App =
                 with _ ->
                     errorResponse 500 "PERSISTENCE_ERROR" "capital deposit persistence failed" next ctx
 
+    let private getCashReconciliation (repository: FundRepository) (fundIdText: string) : HttpHandler =
+        fun next ctx ->
+            match Guid.TryParse fundIdText with
+            | false, _ -> errorResponse 400 "INVALID_FUND_ID" "fund id must be a UUID" next ctx
+            | true, fundId ->
+                try
+                    match repository.GetCashReconciliation fundId with
+                    | Error _ -> errorResponse 404 "FUND_NOT_FOUND" "fund was not found" next ctx
+                    | Ok reconciliation ->
+                        let events = repository.GetCashLedger fundId
+                        json (cashReconciliationResponse fundId reconciliation events) next ctx
+                with _ ->
+                    errorResponse 500 "PERSISTENCE_ERROR" "cash reconciliation failed" next ctx
+
     let private createSipPlan (repository: FundRepository) (fundIdText: string) : HttpHandler =
         fun next ctx ->
             task {
@@ -3555,6 +3631,7 @@ module App =
                 GET >=> routef "/funds/%s/positions" (getPositions repository)
                 POST >=> routef "/funds/%s/capital/deposit" (createCapitalDeposit repository)
                 GET >=> routef "/funds/%s/capital/deposits" (getCapitalDeposits repository)
+                GET >=> routef "/funds/%s/cash-reconciliation" (getCashReconciliation repository)
                 POST >=> routef "/funds/%s/sip/plans" (createSipPlan repository)
                 GET >=> routef "/funds/%s/sip/plans" (getSipPlans repository)
                 POST >=> routef "/funds/%s/sip/advance" (advanceSipPlans repository probes)
diff --git a/src/FundLab.Api/Persistence.fs b/src/FundLab.Api/Persistence.fs
index 267eff3..47c4312 100644
--- a/src/FundLab.Api/Persistence.fs
+++ b/src/FundLab.Api/Persistence.fs
@@ -1019,6 +1019,22 @@ type FundRepository(connectionString: string) =
             created_at timestamptz NOT NULL DEFAULT now()
         );
 
+        CREATE TABLE IF NOT EXISTS cash_ledger_events (
+            id uuid PRIMARY KEY,
+            fund_id uuid NOT NULL REFERENCES funds(id),
+            source_category text NOT NULL,
+            event_date date NOT NULL,
+            amount numeric(20, 2) NOT NULL,
+            reference_type text NOT NULL,
+            reference_id text NOT NULL,
+            note text NULL,
+            created_at timestamptz NOT NULL DEFAULT now(),
+            UNIQUE (fund_id, reference_type, reference_id)
+        );
+
+        CREATE INDEX IF NOT EXISTS cash_ledger_events_fund_idx
+            ON cash_ledger_events (fund_id, event_date, created_at);
+
         CREATE TABLE IF NOT EXISTS sip_plans (
             id uuid PRIMARY KEY,
             fund_id uuid NOT NULL REFERENCES funds(id),
@@ -1683,6 +1699,18 @@ type FundRepository(connectionString: string) =
         addParameter command "fund_id" NpgsqlDbType.Uuid (box fundId) |> ignore
         command.ExecuteNonQuery() |> ignore
 
+    let findOrderIdempotencyKeyByOrderId connection transaction orderId =
+        use command =
+            commandWithTransaction
+                connection
+                transaction
+                "SELECT idempotency_key FROM subscription_order_idempotencies WHERE order_id = @order_id LIMIT 1"
+
+        addParameter command "order_id" NpgsqlDbType.Uuid (box orderId) |> ignore
+
+        use reader = command.ExecuteReader()
+        if reader.Read() then Some(reader.GetString(0)) else None
+
     let upsertInstrument connection transaction (payload: MarketDataSearchPayload) payloadHash (instrument: MarketDataInstrument) =
         use command =
             commandWithTransaction
@@ -2134,6 +2162,48 @@ type FundRepository(connectionString: string) =
         addParameter command "fund_id" NpgsqlDbType.Uuid (box fundId) |> ignore
         command.ExecuteNonQuery() |> ignore
 
+    /// Append a signed cash movement to the ledger. The unique key on
+    /// (fund_id, reference_type, reference_id) makes replays no-ops, so a retried
+    /// operation never double-counts. Callers pass the same delta as the cash UPDATE.
+    let insertCashLedgerEvent
+        connection
+        transaction
+        (fundId: Guid)
+        (source: CashLedger.CashEventSource)
+        (eventDate: DateOnly)
+        (amount: decimal)
+        (referenceType: string)
+        (referenceId: string)
+        (note: string option)
+        =
+        use command =
+            commandWithTransaction
+                connection
+                transaction
+                """
+                INSERT INTO cash_ledger_events
+                    (id, fund_id, source_category, event_date, amount, reference_type, reference_id, note)
+                VALUES
+                    (@id, @fund_id, @source_category, @event_date, @amount, @reference_type, @reference_id, @note)
+                ON CONFLICT (fund_id, reference_type, reference_id) DO NOTHING
+                """
+
+        addParameter command "id" NpgsqlDbType.Uuid (box (Guid.NewGuid())) |> ignore
+        addParameter command "fund_id" NpgsqlDbType.Uuid (box fundId) |> ignore
+        addParameter command "source_category" NpgsqlDbType.Text (box (CashLedger.sourceText source)) |> ignore
+        addParameter command "event_date" NpgsqlDbType.Date (box eventDate) |> ignore
+        addParameter command "amount" NpgsqlDbType.Numeric (box amount) |> ignore
+        addParameter command "reference_type" NpgsqlDbType.Text (box referenceType) |> ignore
+        addParameter command "reference_id" NpgsqlDbType.Text (box referenceId) |> ignore
+
+        let noteParameter =
+            match note with
+            | Some value -> box value
+            | None -> box DBNull.Value
+
+        addParameter command "note" NpgsqlDbType.Text noteParameter |> ignore
+        command.ExecuteNonQuery() |> ignore
+
     let capitalDepositRequestHash (fundId: Guid) (command: CapitalDepositCommand) =
         let invariant = CultureInfo.InvariantCulture
         let encoded (value: string) = sprintf "%d:%s" value.Length value
@@ -5640,6 +5710,18 @@ type FundRepository(connectionString: string) =
 
                                                 let createdAt = insertDividendRecord connection (Some transaction) record
                                                 insertDividendIdempotency connection (Some transaction) schemeKey fingerprint recordId fundId
+
+                                                insertCashLedgerEvent
+                                                    connection
+                                                    (Some transaction)
+                                                    fundId
+                                                    CashLedger.Dividend
+                                                    command.NavDate
+                                                    payout.GrossCash
+                                                    "dividend"
+                                                    (recordId.ToString("D"))
+                                                    None
+
                                                 transaction.Commit()
                                                 StageBooked { record with CreatedAt = createdAt }
                     with error ->
@@ -5843,6 +5925,18 @@ type FundRepository(connectionString: string) =
 
                                 let createdAt = insertCapitalDeposit connection (Some transaction) deposit
                                 insertCapitalDepositIdempotency connection (Some transaction) idempotencyKey fingerprint deposit.Id fundId
+
+                                insertCashLedgerEvent
+                                    connection
+                                    (Some transaction)
+                                    fundId
+                                    CashLedger.CapitalDeposit
+                                    (ConfirmationPolicy.eventDateFor deposit.CreatedAt)
+                                    command.Amount
+                                    "capital_deposit"
+                                    (deposit.Id.ToString("D"))
+                                    None
+
                                 transaction.Commit()
                                 CapitalDepositWriteResult.CapitalDepositCreated { deposit with CreatedAt = createdAt }
                 with error ->
@@ -5943,6 +6037,18 @@ type FundRepository(connectionString: string) =
                                 insertStockTrade connection (Some transaction) trade
                                 insertStockTradeIdempotency connection (Some transaction) idempotencyKey fingerprint trade.Id fundId
 
+                                if defaultArg debitAvailableCash false then
+                                    insertCashLedgerEvent
+                                        connection
+                                        (Some transaction)
+                                        fundId
+                                        CashLedger.StockBuy
+                                        (DateOnly.FromDateTime executedAt.UtcDateTime)
+                                        -costCash
+                                        "stock_buy"
+                                        (trade.Id.ToString("D"))
+                                        None
+
                                 use positionCommand =
                                     commandWithTransaction
                                         connection
@@ -6354,6 +6460,17 @@ type FundRepository(connectionString: string) =
 
                                     insertStockCashflow connection (Some transaction) sellEvent
 
+                                    insertCashLedgerEvent
+                                        connection
+                                        (Some transaction)
+                                        fundId
+                                        CashLedger.StockSell
+                                        (DateOnly.FromDateTime executedAt.UtcDateTime)
+                                        proceeds
+                                        "stock_sell"
+                                        (sell.Id.ToString("D"))
+                                        None
+
                                     transaction.Commit()
                                     StockSellWriteResult.StockSellCreated sell
                     with error ->
@@ -6620,6 +6737,23 @@ type FundRepository(connectionString: string) =
                                 addParameter removeCommand "code" NpgsqlDbType.Text (box normalized.InstrumentCode) |> ignore
                                 removeCommand.ExecuteNonQuery() |> ignore
 
+                            let ledgerSource =
+                                match normalized.EventType with
+                                | "coupon" -> CashLedger.BondCoupon
+                                | "maturity" -> CashLedger.BondMaturity
+                                | _ -> CashLedger.BondSell
+
+                            insertCashLedgerEvent
+                                connection
+                                (Some transaction)
+                                fundId
+                                ledgerSource
+                                record.EventDate
+                                normalized.Amount
+                                "bond_cashflow"
+                                (record.Id.ToString("D"))
+                                None
+
                             transaction.Commit()
                             BondCashflowWriteResult.BondCashflowCreated record
             with error ->
@@ -6825,6 +6959,17 @@ type FundRepository(connectionString: string) =
                                         addParameter positionCommand "code" NpgsqlDbType.Text (box normalized.InstrumentCode) |> ignore
                                         positionCommand.ExecuteNonQuery() |> ignore
 
+                                    insertCashLedgerEvent
+                                        connection
+                                        (Some transaction)
+                                        fundId
+                                        CashLedger.BondSell
+                                        (DateOnly.FromDateTime executedAt.UtcDateTime)
+                                        proceeds
+                                        "bond_sell"
+                                        (record.Id.ToString("D"))
+                                        None
+
                                     transaction.Commit()
                                     BondSellWriteResult.BondSellCreated record
             with error ->
@@ -6914,6 +7059,56 @@ type FundRepository(connectionString: string) =
 
         records |> Seq.toList
 
+    member _.GetCashLedger(fundId: Guid) : CashLedger.CashLedgerEvent list =
+        use connection = new NpgsqlConnection(connectionString)
+        connection.Open()
+
+        use command =
+            commandWithTransaction
+                connection
+                None
+                """
+                SELECT source_category, event_date, amount, reference_type, reference_id, note
+                FROM cash_ledger_events
+                WHERE fund_id = @fund_id
+                ORDER BY event_date, created_at, id
+                """
+
+        addParameter command "fund_id" NpgsqlDbType.Uuid (box fundId) |> ignore
+
+        use reader = command.ExecuteReader()
+        let events = ResizeArray<CashLedger.CashLedgerEvent>()
+
+        while reader.Read() do
+            let source =
+                match CashLedger.parseSource (reader.GetString(0)) with
+                | Some value -> value
+                | None -> failwithf "unknown cash ledger source %s" (reader.GetString(0))
+
+            events.Add(
+                {
+                    CashLedger.Source = source
+                    CashLedger.EventDate = reader.GetFieldValue<DateOnly>(1)
+                    CashLedger.Amount = reader.GetDecimal(2)
+                    CashLedger.ReferenceType = reader.GetString(3)
+                    CashLedger.ReferenceId = reader.GetString(4)
+                    CashLedger.Note = readStringOption reader 5
+                }
+            )
+
+        events |> Seq.toList
+
+    /// Opening cash (the fund's initial capital) plus every ledger movement must equal the
+    /// fund's actual cash (available plus reserved held against pending orders). The
+    /// difference is what the reconciliation endpoint exposes and tests assert is zero.
+    member this.GetCashReconciliation(fundId: Guid) : Result<CashLedger.CashReconciliation, string> =
+        match this.GetFund fundId with
+        | None -> Error "fund was not found"
+        | Some fund ->
+            let events = this.GetCashLedger fundId
+            let ledgerBalance = fund.AvailableCash + fund.ReservedCash
+            Ok(CashLedger.reconcile fund.InitialCash ledgerBalance events)
+
     member _.CreateRedemptionOrder(idempotencyKey: string, fundId: Guid, command: RedemptionCommand) : RedemptionWriteResult =
         if String.IsNullOrWhiteSpace idempotencyKey then
             RedemptionWriteResult.RedemptionInvalid "idempotency key cannot be empty"
@@ -7325,6 +7520,18 @@ type FundRepository(connectionString: string) =
                                     confirmCommand.ExecuteNonQuery() |> ignore
 
                                     insertRedemptionConfirmIdempotency connection (Some transaction) idempotencyKey "" orderId fundId
+
+                                    insertCashLedgerEvent
+                                        connection
+                                        (Some transaction)
+                                        fundId
+                                        CashLedger.Redemption
+                                        tradeDate
+                                        computation.Proceeds
+                                        "redemption"
+                                        (orderId.ToString("D"))
+                                        None
+
                                     transaction.Commit()
 
                                     match findRedemptionOrder connection None orderId with
@@ -7673,6 +7880,22 @@ type FundRepository(connectionString: string) =
                                     addParameter idempotencyCommand "fund_id" NpgsqlDbType.Uuid (box fundId) |> ignore
                                     idempotencyCommand.ExecuteNonQuery() |> ignore
 
+                                    let ledgerSource =
+                                        match findOrderIdempotencyKeyByOrderId connection (Some transaction) orderId with
+                                        | Some key -> CashLedger.subscriptionSourceForKey key
+                                        | None -> CashLedger.Subscription
+
+                                    insertCashLedgerEvent
+                                        connection
+                                        (Some transaction)
+                                        fundId
+                                        ledgerSource
+                                        quote.NavDate
+                                        -(computation.InvestedCash + order.FeeAmount)
+                                        "subscription_settle"
+                                        (orderId.ToString("D"))
+                                        None
+
                                     transaction.Commit()
 
                                     match findOrder connection None orderId with
diff --git a/src/FundLab.Domain/CashLedger.fs b/src/FundLab.Domain/CashLedger.fs
new file mode 100644
index 0000000..d9d8b32
--- /dev/null
+++ b/src/FundLab.Domain/CashLedger.fs
@@ -0,0 +1,118 @@
+namespace FundLab.Domain
+
+open System
+
+/// Cash-ledger event sourcing and reconciliation for a fund. The ledger records every
+/// movement of the fund's cash (available plus reserved) with a source category so the
+/// statement can be grouped and checked against the actual cash balance. Amounts are
+/// signed: positive is an inflow, negative an outflow.
+module CashLedger =
+    /// Source category of a cash movement. The set is the vocabulary surfaced by the
+    /// reconciliation API/UI; not every category is reachable until the corresponding
+    /// operation actually moves cash.
+    type CashEventSource =
+        | Subscription
+        | Redemption
+        | Dividend
+        | Sip
+        | StockBuy
+        | StockSell
+        | BondBuy
+        | BondSell
+        | BondCoupon
+        | BondMaturity
+        | CapitalDeposit
+
+    let sourceText (source: CashEventSource) : string =
+        match source with
+        | Subscription -> "subscription"
+        | Redemption -> "redemption"
+        | Dividend -> "dividend"
+        | Sip -> "sip"
+        | StockBuy -> "stock_buy"
+        | StockSell -> "stock_sell"
+        | BondBuy -> "bond_buy"
+        | BondSell -> "bond_sell"
+        | BondCoupon -> "bond_coupon"
+        | BondMaturity -> "bond_maturity"
+        | CapitalDeposit -> "capital_deposit"
+
+    let parseSource (text: string) : CashEventSource option =
+        match (if isNull text then "" else text.Trim().ToLowerInvariant()) with
+        | "subscription" -> Some Subscription
+        | "redemption" -> Some Redemption
+        | "dividend" -> Some Dividend
+        | "sip" -> Some Sip
+        | "stock_buy" -> Some StockBuy
+        | "stock_sell" -> Some StockSell
+        | "bond_buy" -> Some BondBuy
+        | "bond_sell" -> Some BondSell
+        | "bond_coupon" -> Some BondCoupon
+        | "bond_maturity" -> Some BondMaturity
+        | "capital_deposit" -> Some CapitalDeposit
+        | _ -> None
+
+    /// A scheduled/automated contribution is tagged as SIP; any other subscription key
+    /// is a manual subscription. The key prefix is the only origin signal carried by the
+    /// order pipeline, and it is set by the callers that own the schedule.
+    let subscriptionSourceForKey (key: string) : CashEventSource =
+        let text = if isNull key then "" else key
+
+        if text.StartsWith("sip:", StringComparison.Ordinal)
+           || text.StartsWith("investment-plan:", StringComparison.Ordinal) then
+            Sip
+        else
+            Subscription
+
+    type CashLedgerEvent =
+        {
+            Source: CashEventSource
+            EventDate: DateOnly
+            Amount: decimal
+            ReferenceType: string
+            ReferenceId: string
+            Note: string option
+        }
+
+    type SourceTotal =
+        {
+            Source: CashEventSource
+            NetAmount: decimal
+            EventCount: int
+        }
+
+    type CashReconciliation =
+        {
+            OpeningCash: decimal
+            NetInflow: decimal
+            ClosingCash: decimal
+            LedgerBalance: decimal
+            Difference: decimal
+            Sources: SourceTotal list
+        }
+
+    /// Opening cash plus the net of every ledger event must equal the fund's actual cash
+    /// balance. `Difference` is zero exactly when the ledger fully explains the balance.
+    let reconcile (openingCash: decimal) (ledgerBalance: decimal) (events: CashLedgerEvent list) : CashReconciliation =
+        let netInflow = events |> List.sumBy (fun event -> event.Amount)
+        let closingCash = openingCash + netInflow
+
+        let sources =
+            events
+            |> List.groupBy (fun event -> event.Source)
+            |> List.map (fun (source, group) ->
+                {
+                    Source = source
+                    NetAmount = group |> List.sumBy (fun event -> event.Amount)
+                    EventCount = group.Length
+                })
+            |> List.sortBy (fun total -> sourceText total.Source)
+
+        {
+            OpeningCash = openingCash
+            NetInflow = netInflow
+            ClosingCash = closingCash
+            LedgerBalance = ledgerBalance
+            Difference = closingCash - ledgerBalance
+            Sources = sources
+        }
diff --git a/src/FundLab.Domain/FundLab.Domain.fsproj b/src/FundLab.Domain/FundLab.Domain.fsproj
index 6d6a8ac..7c6db3f 100644
--- a/src/FundLab.Domain/FundLab.Domain.fsproj
+++ b/src/FundLab.Domain/FundLab.Domain.fsproj
@@ -14,6 +14,7 @@
     <Compile Include="InvestmentPlan.fs" />
     <Compile Include="Rebalance.fs" />
     <Compile Include="Dividend.fs" />
+    <Compile Include="CashLedger.fs" />
     <Compile Include="BondRules.fs" />
     <Compile Include="StockRules.fs" />
     <Compile Include="Performance.fs" />
diff --git a/src/FundLab.Web/App.fs b/src/FundLab.Web/App.fs
index 56422ed..232608f 100644
--- a/src/FundLab.Web/App.fs
+++ b/src/FundLab.Web/App.fs
@@ -568,6 +568,35 @@ type RawFundValuation =
         positions: RawValuationPosition array
     }
 
+type RawCashLedgerEvent =
+    {
+        source: string
+        eventDate: string
+        amount: string
+        referenceType: string
+        referenceId: string
+        note: obj
+    }
+
+type RawCashLedgerSource =
+    {
+        source: string
+        netAmount: string
+        eventCount: int
+    }
+
+type RawCashReconciliation =
+    {
+        fundId: string
+        openingCash: string
+        netInflow: string
+        closingCash: string
+        ledgerBalance: string
+        difference: string
+        sources: RawCashLedgerSource array
+        events: RawCashLedgerEvent array
+    }
+
 type RawMarketRefreshTarget =
     {
         instrumentCode: string
@@ -1024,6 +1053,34 @@ type FundValuationView =
         positions: ValuationPositionView list
     }
 
+type CashLedgerEventView =
+    {
+        source: string
+        eventDate: string
+        amount: string
+        referenceType: string
+        referenceId: string
+        note: string option
+    }
+
+type CashLedgerSourceView =
+    {
+        source: string
+        netAmount: string
+        eventCount: int
+    }
+
+type CashReconciliationView =
+    {
+        openingCash: string
+        netInflow: string
+        closingCash: string
+        ledgerBalance: string
+        difference: string
+        sources: CashLedgerSourceView list
+        events: CashLedgerEventView list
+    }
+
 type BondTradeAttempt =
     {
         idempotencyKey: string
@@ -1113,6 +1170,9 @@ module Api =
     [<Import("getFundValuation", "./src/api.js")>]
     let getFundValuation (token: string) (fundId: string) : JS.Promise<RawFundValuation> = jsNative
 
+    [<Import("getCashReconciliation", "./src/api.js")>]
+    let getCashReconciliation (token: string) (fundId: string) : JS.Promise<RawCashReconciliation> = jsNative
+
     [<Import("refreshFundMarketData", "./src/api.js")>]
     let refreshFundMarketData (token: string) (fundId: string) : JS.Promise<RawMarketRefresh> = jsNative
 
@@ -1495,6 +1555,34 @@ module Api =
             positions = raw.positions |> Array.toList |> List.map decodeValuationPosition
         }
 
+    let decodeCashLedgerEvent (raw: RawCashLedgerEvent) : CashLedgerEventView =
+        {
+            source = raw.source
+            eventDate = raw.eventDate
+            amount = raw.amount
+            referenceType = raw.referenceType
+            referenceId = raw.referenceId
+            note = Option.ofObj raw.note |> Option.map string
+        }
+
+    let decodeCashLedgerSource (raw: RawCashLedgerSource) : CashLedgerSourceView =
+        {
+            source = raw.source
+            netAmount = raw.netAmount
+            eventCount = raw.eventCount
+        }
+
+    let decodeCashReconciliation (raw: RawCashReconciliation) : CashReconciliationView =
+        {
+            openingCash = raw.openingCash
+            netInflow = raw.netInflow
+            closingCash = raw.closingCash
+            ledgerBalance = raw.ledgerBalance
+            difference = raw.difference
+            sources = raw.sources |> Array.toList |> List.map decodeCashLedgerSource
+            events = raw.events |> Array.toList |> List.map decodeCashLedgerEvent
+        }
+
 type Model =
     {
         token: string
@@ -1633,6 +1721,11 @@ type Model =
         valuationInFlight: bool
         valuation: FundValuationView option
         valuationMessage: string option
+        cashLedgerReadSeq: int
+        cashLedgerInFlight: bool
+        cashReconciliation: CashReconciliationView option
+        cashLedgerMessage: string option
+        cashLedgerFilter: string
         marketRefreshSeq: int
         marketRefreshInFlight: bool
         marketRefreshMessage: string option
@@ -1782,6 +1875,10 @@ type Msg =
     | ValuationReadRequested
     | ValuationReadCompleted of requestId: int * fundId: string * valuation: RawFundValuation
     | ValuationReadFailed of requestId: int * fundId: string * message: string
+    | CashLedgerReadRequested
+    | CashLedgerReadCompleted of requestId: int * fundId: string * reconciliation: RawCashReconciliation
+    | CashLedgerReadFailed of requestId: int * fundId: string * message: string
+    | CashLedgerFilterChanged of string
     | MarketRefreshRequested
     | MarketRefreshCompleted of requestId: int * fundId: string * response: RawMarketRefresh
     | MarketRefreshFailed of requestId: int * fundId: string * message: string
@@ -1968,6 +2065,11 @@ let init () =
         valuationInFlight = false
         valuation = None
         valuationMessage = None
+        cashLedgerReadSeq = 0
+        cashLedgerInFlight = false
+        cashReconciliation = None
+        cashLedgerMessage = None
+        cashLedgerFilter = ""
         marketRefreshSeq = 0
         marketRefreshInFlight = false
         marketRefreshMessage = None
@@ -2260,6 +2362,13 @@ let private refreshMarketDataCommand token fundId requestId =
         (fun response -> MarketRefreshCompleted(requestId, fundId, response))
         (fun error -> MarketRefreshFailed(requestId, fundId, errorText error))
 
+let private readCashLedgerCommand token fundId requestId =
+    Cmd.OfPromise.either
+        (fun () -> Api.getCashReconciliation token fundId)
+        ()
+        (fun reconciliation -> CashLedgerReadCompleted(requestId, fundId, reconciliation))
+        (fun error -> CashLedgerReadFailed(requestId, fundId, errorText error))
+
 let private readInvestmentPlansCommand token fundId requestId =
     Cmd.OfPromise.either
         (fun () -> Api.getInvestmentPlans token fundId)
@@ -2982,7 +3091,7 @@ let update message model =
                     capitalNote = Some(sprintf "追加成功 + %s（现金余额已刷新）" amount)
                     error = None
             },
-            Cmd.batch [ Cmd.ofMsg FundReadRequested; Cmd.ofMsg ReturnsReadRequested ]
+            Cmd.batch [ Cmd.ofMsg FundReadRequested; Cmd.ofMsg ReturnsReadRequested; Cmd.ofMsg CashLedgerReadRequested ]
         else
             model, Cmd.none
     | CapitalDepositFailed (requestId, message) ->
@@ -3822,7 +3931,7 @@ let update message model =
                     stockSellQuantities = Map.remove code model.stockSellQuantities
                     stockSellAttempts = Map.remove code model.stockSellAttempts
             },
-            Cmd.batch [ Cmd.ofMsg StockPositionsReadRequested; Cmd.ofMsg ValuationReadRequested ]
+            Cmd.batch [ Cmd.ofMsg StockPositionsReadRequested; Cmd.ofMsg ValuationReadRequested; Cmd.ofMsg CashLedgerReadRequested ]
         else
             model, Cmd.none
     | StockSellFailed (requestId, fundId, code, message) ->
@@ -4056,6 +4165,44 @@ let update message model =
             Cmd.none
         else
             model, Cmd.none
+    | CashLedgerReadRequested ->
+        match model.createdFund with
+        | Some fund when not (String.IsNullOrWhiteSpace model.token) ->
+            let requestId = model.cashLedgerReadSeq + 1
+
+            {
+                model with
+                    cashLedgerReadSeq = requestId
+                    cashLedgerInFlight = true
+                    cashLedgerMessage = None
+            },
+            readCashLedgerCommand model.token fund.id requestId
+        | _ -> model, Cmd.none
+    | CashLedgerReadCompleted (requestId, fundId, reconciliation) ->
+        if requestId = model.cashLedgerReadSeq
+           && (match model.createdFund with Some fund -> fund.id = fundId | None -> false) then
+            {
+                model with
+                    cashReconciliation = Some(Api.decodeCashReconciliation reconciliation)
+                    cashLedgerInFlight = false
+                    cashLedgerMessage = None
+            },
+            Cmd.none
+        else
+            model, Cmd.none
+    | CashLedgerReadFailed (requestId, fundId, message) ->
+        if requestId = model.cashLedgerReadSeq
+           && (match model.createdFund with Some fund -> fund.id = fundId | None -> false) then
+            {
+                model with
+                    cashReconciliation = None
+                    cashLedgerInFlight = false
+                    cashLedgerMessage = Some(sprintf "现金账不可用 — %s" message)
+            },
+            Cmd.none
+        else
+            model, Cmd.none
+    | CashLedgerFilterChanged value -> { model with cashLedgerFilter = value }, Cmd.none
     | MarketRefreshRequested ->
         match model.createdFund with
         | Some fund when not (String.IsNullOrWhiteSpace model.token) ->
@@ -6246,6 +6393,95 @@ let private stocksPanel model dispatch =
                     ]
                 ]
             ]
+            Html.div [
+                prop.className "fund-cash-ledger"
+                prop.children [
+                    Html.p [ prop.className "returns-subheading"; prop.text "现金账对账" ]
+                    Html.div [
+                        prop.className "search-row"
+                        prop.children [
+                            Html.button [
+                                prop.className "secondary-action cash-ledger-refresh-action"
+                                prop.disabled model.cashLedgerInFlight
+                                prop.onClick (fun _ -> dispatch CashLedgerReadRequested)
+                                prop.text ((if model.cashLedgerInFlight then "加载中..." else "刷新现金账"): string)
+                            ]
+                            Html.select [
+                                prop.className "cash-ledger-filter"
+                                prop.value model.cashLedgerFilter
+                                prop.onChange (fun (value: string) -> dispatch (CashLedgerFilterChanged value))
+                                prop.children (
+                                    [ Html.option [ prop.value ""; prop.text "全部来源" ] ]
+                                    @ (match model.cashReconciliation with
+                                       | Some reconciliation ->
+                                           reconciliation.sources
+                                           |> List.map (fun source -> Html.option [ prop.value source.source; prop.text source.source ])
+                                       | None -> [])
+                                )
+                            ]
+                        ]
+                    ]
+                    match model.cashReconciliation with
+                    | Some reconciliation ->
+                        let filteredEvents =
+                            if model.cashLedgerFilter = "" then
+                                reconciliation.events
+                            else
+                                reconciliation.events |> List.filter (fun event -> event.source = model.cashLedgerFilter)
+
+                        Html.div [
+                            prop.className "cash-ledger-content"
+                            prop.children (
+                                [ Html.div [
+                                      prop.className "metric-strip cash-ledger-metrics"
+                                      prop.children [
+                                          bondQuoteMetric "期初现金" (Some reconciliation.openingCash)
+                                          bondQuoteMetric "净流入" (Some reconciliation.netInflow)
+                                          bondQuoteMetric "期末现金" (Some reconciliation.closingCash)
+                                          bondQuoteMetric "账实差异" (Some reconciliation.difference)
+                                      ]
+                                  ]
+                                  Html.div [
+                                      prop.className "cash-ledger-sources"
+                                      prop.children (
+                                          reconciliation.sources
+                                          |> List.map (fun source ->
+                                              Html.div [
+                                                  prop.className "cash-ledger-source-row"
+                                                  prop.children [
+                                                      Html.span [ prop.className "fund-detail-label"; prop.text source.source ]
+                                                      Html.span [ prop.className "fund-detail-value"; prop.text source.netAmount ]
+                                                      Html.span [ prop.className "fund-detail-value"; prop.text (sprintf "%d 笔" source.eventCount) ]
+                                                  ]
+                                              ])
+                                      )
+                                  ]
+                                  Html.div [
+                                      prop.className "cash-ledger-events"
+                                      prop.children (
+                                          filteredEvents
+                                          |> List.map (fun event ->
+                                              Html.div [
+                                                  prop.className "cash-ledger-event-row"
+                                                  prop.children [
+                                                      Html.span [ prop.className "fund-detail-value"; prop.text event.eventDate ]
+                                                      Html.span [ prop.className "fund-detail-label"; prop.text event.source ]
+                                                      Html.span [ prop.className "fund-detail-value"; prop.text event.amount ]
+                                                      Html.span [ prop.className "fund-detail-value"; prop.text (event.note |> Option.defaultValue "—") ]
+                                                  ]
+                                              ])
+                                      )
+                                  ] ]
+                            )
+                        ]
+                    | None -> Html.p [ prop.className "hint"; prop.text "刷新后显示按来源分组的现金流水与账实对账；期末现金 = 期初 + 净流入，差异应为 0。" ]
+                    Html.p [
+                        prop.className "cash-ledger-unavailable"
+                        prop.hidden (model.cashLedgerMessage.IsNone)
+                        prop.text (model.cashLedgerMessage |> Option.defaultValue "")
+                    ]
+                ]
+            ]
         ]
     ]
 
diff --git a/src/FundLab.Web/src/api.js b/src/FundLab.Web/src/api.js
index 3136371..26336ea 100644
--- a/src/FundLab.Web/src/api.js
+++ b/src/FundLab.Web/src/api.js
@@ -211,6 +211,10 @@ export function getFundValuation(token, fundId) {
   return requestJson(`/api/funds/${encodeURIComponent(fundId)}/valuation`, token);
 }
 
+export function getCashReconciliation(token, fundId) {
+  return requestJson(`/api/funds/${encodeURIComponent(fundId)}/cash-reconciliation`, token);
+}
+
 export function refreshFundMarketData(token, fundId, asOfDate) {
   const suffix = asOfDate ? `?asOfDate=${encodeURIComponent(asOfDate)}` : "";
   return requestJson(`/api/funds/${encodeURIComponent(fundId)}/market-data/refresh${suffix}`, token, {
diff --git a/tests/FundLab.Api.Tests/CashReconciliationTests.fs b/tests/FundLab.Api.Tests/CashReconciliationTests.fs
new file mode 100644
index 0000000..59f6fd6
--- /dev/null
+++ b/tests/FundLab.Api.Tests/CashReconciliationTests.fs
@@ -0,0 +1,254 @@
+namespace FundLab.Api.Tests
+
+open System
+open System.Text.Json
+open Xunit
+open FundLab.Api
+open FundLab.Domain
+
+[<Collection("postgres")>]
+type CashReconciliationTests(fixture: PostgresFixture) =
+    let sharedRepository =
+        lazy
+            let value = FundRepository(fixture.ConnectionString)
+            value.EnsureSchema()
+            value
+
+    let repository () = sharedRepository.Value
+
+    let today = ConfirmationPolicy.tradeDateFor DateTimeOffset.UtcNow
+
+    let createFund (initialCash: decimal) =
+        let command =
+            {
+                Name = "现金对账测试 FOF"
+                InitialCash = initialCash
+                InitialUnitNav = 1.00000000m
+                IsSynthetic = true
+            }
+
+        let key = fixture.Key(sprintf "cash-recon-fund-%s" (Guid.NewGuid().ToString("N")))
+
+        match repository().CreateFund(key, command) with
+        | FundWriteResult.Created fund -> fund.Id
+        | other -> failwithf "unexpected fund creation result: %A" other
+
+    let seedInstrument () =
+        let code = Random.Shared.Next(0, 1000000).ToString("D6")
+
+        let payload =
+            {
+                Source = "akshare"
+                SourceRevision = "akshare-test/eastmoney"
+                CollectedAt = DateTimeOffset(2026, 9, 21, 8, 0, 0, TimeSpan.Zero)
+                Instruments = [ { Code = code; Name = "现金对账测试基金"; FundType = None } ]
+            }
+
+        repository().UpsertInstruments(payload, "cash-recon-test-hash")
+        code
+
+    let insertQuoteOnDate (code: string) (nav: decimal) (navDate: DateOnly) =
+        let revision = sprintf "cash-recon-test/%O" (Guid.NewGuid())
+
+        let payload: MarketDataNavPayload =
+            {
+                Source = "akshare"
+                SourceRevision = revision
+                CollectedAt = DateTimeOffset.UtcNow.AddSeconds(-10.0)
+                Code = code
+                Observations =
+                    [
+                        {
+                            NavDate = navDate
+                            PublishedAt = None
+                            Nav = nav
+                            AccumulatedNav = Some nav
+                            DailyReturn = Some 0.0m
+                        }
+                    ]
+            }
+
+        repository().UpsertNavObservations(payload, sprintf "cash-recon-hash/%s" revision)
+
+    let deposit fundId amount idempotencyKey =
+        match
+            repository().CreateCapitalDeposit(
+                idempotencyKey,
+                fundId,
+                { Amount = amount; Note = Some "追加" }
+            )
+        with
+        | CapitalDepositWriteResult.CapitalDepositCreated _
+        | CapitalDepositWriteResult.CapitalDepositReplayed _ -> ()
+        | other -> failwithf "unexpected deposit result: %A" other
+
+    let buyStockDebit fundId code quantity price idempotencyKey =
+        match
+            repository().CreateStockTrade(
+                idempotencyKey,
+                fundId,
+                { InstrumentCode = code; StockName = Some "贵州茅台"; Quantity = quantity; Price = price },
+                debitAvailableCash = true
+            )
+        with
+        | StockTradeWriteResult.StockTradeCreated _
+        | StockTradeWriteResult.StockTradeReplayed _ -> ()
+        | other -> failwithf "unexpected stock trade result: %A" other
+
+    let sellStock fundId code quantity price idempotencyKey =
+        match
+            repository().CreateStockSell(
+                idempotencyKey,
+                fundId,
+                { InstrumentCode = code; StockName = Some "贵州茅台"; Quantity = quantity; Price = price; FeeAmount = 0m }
+            )
+        with
+        | StockSellWriteResult.StockSellCreated _
+        | StockSellWriteResult.StockSellReplayed _ -> ()
+        | other -> failwithf "unexpected stock sell result: %A" other
+
+    let buyBond fundId code quantity price =
+        match
+            repository().CreateBondTrade(
+                fixture.Key(sprintf "cash-recon-bond-%s" (Guid.NewGuid().ToString("N"))),
+                fundId,
+                {
+                    InstrumentCode = code
+                    BondName = Some "南航转债"
+                    Quantity = quantity
+                    Price = price
+                    CleanPrice = price
+                    AccruedInterest = 0m
+                    ParValue = 100m
+                    SettlementDate = today
+                    CouponRate = None
+                    ValueDate = None
+                    MaturityDate = None
+                    TradeDate = Some today
+                }
+            )
+        with
+        | BondTradeWriteResult.BondTradeCreated _ -> ()
+        | other -> failwithf "unexpected bond trade result: %A" other
+
+    let recordBondCoupon fundId code amount idempotencyKey =
+        match
+            repository().RecordBondCashflow(
+                idempotencyKey,
+                fundId,
+                {
+                    InstrumentCode = code
+                    BondName = Some "南航转债"
+                    EventType = "coupon"
+                    EventDate = today
+                    Quantity = 10m
+                    Amount = amount
+                    Note = None
+                }
+            )
+        with
+        | BondCashflowWriteResult.BondCashflowCreated _
+        | BondCashflowWriteResult.BondCashflowReplayed _ -> ()
+        | other -> failwithf "unexpected bond cashflow result: %A" other
+
+    let subscribe fundId code amount idempotencyKey =
+        insertQuoteOnDate code 1.0m today
+
+        let order =
+            match
+                repository().CreateSubscriptionOrder(
+                    idempotencyKey,
+                    fundId,
+                    { FundCode = code; Amount = amount; FeeAmount = 0m },
+                    today
+                )
+            with
+            | SubscriptionOrderWriteResult.OrderCreated order
+            | SubscriptionOrderWriteResult.OrderReplayed order -> order
+            | other -> failwithf "unexpected subscription order result: %A" other
+
+        match
+            repository().ConfirmSubscriptionOrder(
+                fixture.Key(sprintf "cash-recon-confirm-%s" (Guid.NewGuid().ToString("N"))),
+                fundId,
+                order.Id
+            )
+        with
+        | SubscriptionConfirmResult.OrderConfirmed _ -> ()
+        | other -> failwithf "unexpected subscription confirm: %A" other
+
+    let app () = App.createApplication (repository ())
+
+    let reconciliation fundId =
+        PersistenceTestHelpers.invoke
+            (app ())
+            "GET"
+            (sprintf "/api/funds/%O/cash-reconciliation" fundId)
+            [ "Authorization", "Bearer test-token" ]
+            ""
+
+    let sourceEntry (body: string) (source: string) =
+        use document = JsonDocument.Parse(body)
+
+        document.RootElement.GetProperty("sources").EnumerateArray()
+        |> Seq.find (fun entry -> entry.GetProperty("source").GetString() = source)
+        |> fun entry -> entry.Clone()
+
+    let eventCount (body: string) (source: string) =
+        use document = JsonDocument.Parse(body)
+
+        document.RootElement.GetProperty("events").EnumerateArray()
+        |> Seq.filter (fun entry -> entry.GetProperty("source").GetString() = source)
+        |> Seq.length
+
+    [<Fact>]
+    member _.``cash reconciliation balances across every source category``() =
+        let fundId = createFund 10000.00m
+        deposit fundId 5000.00m (fixture.Key "cash-recon-deposit")
+        buyStockDebit fundId "600519" 100m 10.00m (fixture.Key "cash-recon-buy")
+        sellStock fundId "600519" 40m 10.00m (fixture.Key "cash-recon-sell")
+        buyBond fundId "110075" 10m 100.00m
+        recordBondCoupon fundId "110075" 50.00m (fixture.Key "cash-recon-coupon")
+        subscribe fundId (seedInstrument ()) 1000.00m (fixture.Key "cash-recon-subscribe")
+
+        let status, body = reconciliation fundId
+        Assert.Equal(200, status)
+        Assert.Contains("\"openingCash\":\"10000.00\"", body)
+        Assert.Contains("\"netInflow\":\"3450.00\"", body)
+        Assert.Contains("\"closingCash\":\"13450.00\"", body)
+        Assert.Contains("\"ledgerBalance\":\"13450.00\"", body)
+        Assert.Contains("\"difference\":\"0.00\"", body)
+
+        Assert.Equal("5000.00", (sourceEntry body "capital_deposit").GetProperty("netAmount").GetString())
+        Assert.Equal("-1000.00", (sourceEntry body "stock_buy").GetProperty("netAmount").GetString())
+        Assert.Equal("400.00", (sourceEntry body "stock_sell").GetProperty("netAmount").GetString())
+        Assert.Equal("50.00", (sourceEntry body "bond_coupon").GetProperty("netAmount").GetString())
+        Assert.Equal("-1000.00", (sourceEntry body "subscription").GetProperty("netAmount").GetString())
+
+        // every category reconciles to zero, i.e. no unexplained cash movement
+        Assert.Equal(0.00m, (repository().GetCashReconciliation fundId |> Result.defaultWith failwith).Difference)
+
+    [<Fact>]
+    member _.``replayed operations do not double count ledger events``() =
+        let fundId = createFund 1000.00m
+        let depositKey = fixture.Key "cash-recon-idem-deposit"
+        let buyKey = fixture.Key "cash-recon-idem-buy"
+
+        deposit fundId 500.00m depositKey
+        deposit fundId 500.00m depositKey
+        buyStockDebit fundId "600519" 100m 10.00m buyKey
+        buyStockDebit fundId "600519" 100m 10.00m buyKey
+
+        let status, body = reconciliation fundId
+        Assert.Equal(200, status)
+        Assert.Contains("\"difference\":\"0.00\"", body)
+        Assert.Contains("\"ledgerBalance\":\"500.00\"", body) // 1000 + 500 - 1000
+
+        Assert.Equal(1, eventCount body "capital_deposit")
+        Assert.Equal(1, eventCount body "stock_buy")
+
+    [<Fact>]
+    member _.``reconciliation for a missing fund answers 404``() =
+        let status, body = reconciliation (Guid.NewGuid())
+        Assert.Equal(404, status)
+        Assert.Contains("FUND_NOT_FOUND", body)
diff --git a/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj b/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
index f37dce4..66cc2aa 100644
--- a/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
+++ b/tests/FundLab.Api.Tests/FundLab.Api.Tests.fsproj
@@ -43,6 +43,7 @@
         <Compile Include="SipPlanStatusTests.fs" />
         <Compile Include="RebalanceArchiveTests.fs" />
         <Compile Include="RebalanceStockTests.fs" />
+        <Compile Include="CashReconciliationTests.fs" />
     <Compile Include="Program.fs" />
   </ItemGroup>
 </Project>
diff --git a/tests/FundLab.Domain.Tests/DomainTests.fs b/tests/FundLab.Domain.Tests/DomainTests.fs
index 63bcab2..c3d4551 100644
--- a/tests/FundLab.Domain.Tests/DomainTests.fs
+++ b/tests/FundLab.Domain.Tests/DomainTests.fs
@@ -880,3 +880,84 @@ module DividendPolicyTests =
 
         Assert.Equal("dividend:7c9e6679-7425-40de-944b-e07fc1f90ae7", DividendPolicy.recordKey recordId)
         Assert.Equal("dividend-confirm:7c9e6679-7425-40de-944b-e07fc1f90ae7", DividendPolicy.confirmKey recordId)
+
+module CashLedgerTests =
+
+    open System
+    open Xunit
+    open FundLab.Domain
+
+    let private event source amount : CashLedger.CashLedgerEvent =
+        {
+            Source = source
+            EventDate = DateOnly(2026, 9, 21)
+            Amount = amount
+            ReferenceType = "test"
+            ReferenceId = Guid.NewGuid().ToString("D")
+            Note = None
+        }
+
+    [<Fact>]
+    let ``cash source text roundtrips through parse`` () =
+        let sources =
+            [
+                CashLedger.Subscription
+                CashLedger.Redemption
+                CashLedger.Dividend
+                CashLedger.Sip
+                CashLedger.StockBuy
+                CashLedger.StockSell
+                CashLedger.BondBuy
+                CashLedger.BondSell
+                CashLedger.BondCoupon
+                CashLedger.BondMaturity
+                CashLedger.CapitalDeposit
+            ]
+
+        for source in sources do
+            Assert.Equal(Some source, CashLedger.parseSource (CashLedger.sourceText source))
+
+        Assert.Equal(None, CashLedger.parseSource "unknown")
+
+    [<Fact>]
+    let ``scheduled contribution keys are tagged as sip`` () =
+        Assert.Equal(CashLedger.Sip, CashLedger.subscriptionSourceForKey "sip:plan:2026-09-21")
+        Assert.Equal(CashLedger.Sip, CashLedger.subscriptionSourceForKey "investment-plan:abc:2026-09-21")
+        Assert.Equal(CashLedger.Subscription, CashLedger.subscriptionSourceForKey "manual-key")
+        Assert.Equal(CashLedger.Subscription, CashLedger.subscriptionSourceForKey null)
+
+    [<Fact>]
+    let ``reconciliation groups sources and balances`` () =
+        let events =
+            [
+                event CashLedger.CapitalDeposit 5000.00m
+                event CashLedger.StockBuy -1000.00m
+                event CashLedger.StockSell 400.00m
+                event CashLedger.StockSell 100.00m
+            ]
+
+        let reconciliation = CashLedger.reconcile 10000.00m 14500.00m events
+
+        Assert.Equal(10000.00m, reconciliation.OpeningCash)
+        Assert.Equal(4500.00m, reconciliation.NetInflow)
+        Assert.Equal(14500.00m, reconciliation.ClosingCash)
+        Assert.Equal(14500.00m, reconciliation.LedgerBalance)
+        Assert.Equal(0m, reconciliation.Difference)
+
+        let bySource =
+            reconciliation.Sources |> List.map (fun total -> CashLedger.sourceText total.Source, total.NetAmount, total.EventCount)
+
+        Assert.Equal<(string * decimal * int) list>(
+            [ ("capital_deposit", 5000.00m, 1); ("stock_buy", -1000.00m, 1); ("stock_sell", 500.00m, 2) ],
+            bySource
+        )
+
+    [<Fact>]
+    let ``reconciliation reports a non-zero difference`` () =
+        let reconciliation = CashLedger.reconcile 10000.00m 9000.00m [ event CashLedger.StockBuy -500.00m ]
+        Assert.Equal(9500.00m, reconciliation.ClosingCash)
+        Assert.Equal(500.00m, reconciliation.Difference)
+
+        let empty = CashLedger.reconcile 100.00m 100.00m []
+        Assert.Equal(0m, empty.Difference)
+        Assert.Empty(empty.Sources)