handle stock split

internal/filler.go

@@ -9,19 +9,27 @@ import (
 type Filler struct {
 	Record
 
-	filled decimal.Decimal
+	filled   decimal.Decimal
+	quantity decimal.Decimal
+	price    decimal.Decimal
 }
 
 func NewFiller(r Record) *Filler {
 	return &Filler{
-		Record: r,
+		Record:   r,
+		quantity: r.Quantity(),
+		price:    r.Price(),
 	}
 }
 
+func (f *Filler) Quantity() decimal.Decimal { return f.quantity }
+
+func (f *Filler) Price() decimal.Decimal { return f.price }
+
 // Fill accrues some quantity. Returns how mutch was accrued in the 1st return value and whether
 // it was filled or not on the 2nd return value.
 func (f *Filler) Fill(quantity decimal.Decimal) (decimal.Decimal, bool) {
-	unfilled := f.Record.Quantity().Sub(f.filled)
+	unfilled := f.quantity.Sub(f.filled)
 	delta := decimal.Min(unfilled, quantity)
 	f.filled = f.filled.Add(delta)
 	return delta, f.IsFilled()
@@ -29,7 +37,15 @@ func (f *Filler) Fill(quantity decimal.Decimal) (decimal.Decimal, bool) {
 
 // IsFilled returns true if the fill is equal to the record quantity.
 func (f *Filler) IsFilled() bool {
-	return f.filled.Equal(f.Quantity())
+	return f.filled.Equal(f.quantity)
+}
+
+// ApplySplit adjusts the lot for a stock split by the given ratio (newQty/oldQty).
+// The total cost basis is preserved: quantity scales up, price scales down proportionally.
+func (f *Filler) ApplySplit(ratio decimal.Decimal) {
+	f.quantity = f.quantity.Mul(ratio)
+	f.filled = f.filled.Mul(ratio)
+	f.price = f.price.Div(ratio)
 }
 
 type FillerQueue struct {
@@ -86,6 +102,16 @@ func (fq *FillerQueue) frontElement() *list.Element {
 	return fq.l.Front()
 }
 
+// AdjustForSplit applies a stock split ratio to all lots in the queue.
+func (fq *FillerQueue) AdjustForSplit(ratio decimal.Decimal) {
+	if fq == nil || fq.l == nil {
+		return
+	}
+	for e := fq.l.Front(); e != nil; e = e.Next() {
+		e.Value.(*Filler).ApplySplit(ratio)
+	}
+}
+
 // Len returns how many elements are currently on the queue
 func (fq *FillerQueue) Len() int {
 	if fq == nil || fq.l == nil {

internal/filler_test.go

@@ -114,7 +114,7 @@ func TestFillerQueueNilReceiver(t *testing.T) {
 			t.Fatalf(`want panic message %q but got "%v"`, expMsg, r)
 		}
 	}()
-	rq.Push(NewFiller(nil))
+	rq.Push(NewFiller(&testRecord{}))
 }
 
 type testRecord struct {
@@ -122,11 +122,11 @@ type testRecord struct {
 
 	id       int
 	quantity decimal.Decimal
+	price    decimal.Decimal
 }
 
-func (tr testRecord) Quantity() decimal.Decimal {
-	return tr.quantity
-}
+func (tr testRecord) Quantity() decimal.Decimal { return tr.quantity }
+func (tr testRecord) Price() decimal.Decimal    { return tr.price }
 
 func TestFiller_Fill(t *testing.T) {
 	tests := []struct {
@@ -185,3 +185,89 @@ func TestFiller_Fill(t *testing.T) {
 		})
 	}
 }
+
+func TestFiller_ApplySplit(t *testing.T) {
+	tests := []struct {
+		name          string
+		qty           float64
+		price         float64
+		prefilled     float64
+		ratio         float64
+		wantQty       float64
+		wantPrice     float64
+		wantFilled    float64
+		wantCostBasis float64
+	}{
+		{
+			name: "5:1 split on unfilled lot preserves cost basis",
+			qty:  10, price: 100, prefilled: 0, ratio: 5,
+			wantQty: 50, wantPrice: 20, wantFilled: 0, wantCostBasis: 1000,
+		},
+		{
+			name: "5:1 split on partially filled lot",
+			qty:  10, price: 100, prefilled: 4, ratio: 5,
+			wantQty: 50, wantPrice: 20, wantFilled: 20, wantCostBasis: 1000,
+		},
+		{
+			name: "1:2 reverse split on unfilled lot preserves cost basis",
+			qty:  10, price: 100, prefilled: 0, ratio: 0.5,
+			wantQty: 5, wantPrice: 200, wantFilled: 0, wantCostBasis: 1000,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			f := NewFiller(&testRecord{
+				quantity: decimal.NewFromFloat(tt.qty),
+				price:    decimal.NewFromFloat(tt.price),
+			})
+			if tt.prefilled > 0 {
+				f.Fill(decimal.NewFromFloat(tt.prefilled))
+			}
+
+			f.ApplySplit(decimal.NewFromFloat(tt.ratio))
+
+			if !f.Quantity().Equal(decimal.NewFromFloat(tt.wantQty)) {
+				t.Errorf("want quantity %v but got %v", tt.wantQty, f.Quantity())
+			}
+			if !f.Price().Equal(decimal.NewFromFloat(tt.wantPrice)) {
+				t.Errorf("want price %v but got %v", tt.wantPrice, f.Price())
+			}
+			if !f.filled.Equal(decimal.NewFromFloat(tt.wantFilled)) {
+				t.Errorf("want filled %v but got %v", tt.wantFilled, f.filled)
+			}
+			costBasis := f.Quantity().Mul(f.Price())
+			if !costBasis.Equal(decimal.NewFromFloat(tt.wantCostBasis)) {
+				t.Errorf("want cost basis %v but got %v", tt.wantCostBasis, costBasis)
+			}
+		})
+	}
+}
+
+func TestFillerQueue_AdjustForSplit(t *testing.T) {
+	var fq FillerQueue
+	fq.Push(NewFiller(&testRecord{quantity: decimal.NewFromFloat(10), price: decimal.NewFromFloat(100)}))
+	fq.Push(NewFiller(&testRecord{quantity: decimal.NewFromFloat(5), price: decimal.NewFromFloat(200)}))
+
+	fq.AdjustForSplit(decimal.NewFromFloat(5))
+
+	lot1, _ := fq.Pop()
+	if !lot1.Quantity().Equal(decimal.NewFromFloat(50)) {
+		t.Errorf("lot1: want quantity 50 but got %v", lot1.Quantity())
+	}
+	if !lot1.Price().Equal(decimal.NewFromFloat(20)) {
+		t.Errorf("lot1: want price 20 but got %v", lot1.Price())
+	}
+
+	lot2, _ := fq.Pop()
+	if !lot2.Quantity().Equal(decimal.NewFromFloat(25)) {
+		t.Errorf("lot2: want quantity 25 but got %v", lot2.Quantity())
+	}
+	if !lot2.Price().Equal(decimal.NewFromFloat(40)) {
+		t.Errorf("lot2: want price 40 but got %v", lot2.Price())
+	}
+}
+
+func TestFillerQueue_AdjustForSplit_NilReceiver(t *testing.T) {
+	var fq *FillerQueue
+	fq.AdjustForSplit(decimal.NewFromFloat(5)) // must not panic
+}

internal/kind.go

@@ -0,0 +1,30 @@
+package internal
+
+type Kind uint
+
+const (
+	KindUnknown Kind = iota
+	KindBuy
+	KindSell
+	KindSplit
+)
+
+// String returns a human readable value
+func (d Kind) String() string {
+	switch d {
+	case KindBuy:
+		return "buy"
+	case KindSell:
+		return "sell"
+	case KindSplit:
+		return "split"
+	default:
+		return "unknown"
+	}
+}
+
+// Is returns true when k equals o
+func (k Kind) Is(o any) bool {
+	other, ok := o.(Kind)
+	return ok && k == other
+}

internal/kind_test.go

@@ -5,12 +5,12 @@ import "testing"
 func TestSide_String(t *testing.T) {
 	tests := []struct {
 		name string
-		side Side
+		side Kind
 		want string
 	}{
-		{"buy", SideBuy, "buy"},
-		{"sell", SideSell, "sell"},
-		{"unknown", SideUnknown, "unknown"},
+		{"buy", KindBuy, "buy"},
+		{"sell", KindSell, "sell"},
+		{"unknown", KindUnknown, "unknown"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -24,16 +24,16 @@ func TestSide_String(t *testing.T) {
 func TestSide_IsBuy(t *testing.T) {
 	tests := []struct {
 		name string
-		side Side
+		side Kind
 		want bool
 	}{
-		{"buy", SideBuy, true},
-		{"sell", SideSell, false},
-		{"unknown", SideUnknown, false},
+		{"buy", KindBuy, true},
+		{"sell", KindSell, false},
+		{"unknown", KindUnknown, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := tt.side.IsBuy(); got != tt.want {
+			if got := tt.side.Is(KindBuy); got != tt.want {
 				t.Errorf("want Side.IsBuy() to be %v but got %v", tt.want, got)
 			}
 		})
@@ -43,16 +43,16 @@ func TestSide_IsBuy(t *testing.T) {
 func TestSide_IsSell(t *testing.T) {
 	tests := []struct {
 		name string
-		side Side
+		side Kind
 		want bool
 	}{
-		{"buy", SideBuy, false},
-		{"sell", SideSell, true},
-		{"unknown", SideUnknown, false},
+		{"buy", KindBuy, false},
+		{"sell", KindSell, true},
+		{"unknown", KindUnknown, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := tt.side.IsSell(); got != tt.want {
+			if got := tt.side.Is(KindSell); got != tt.want {
 				t.Errorf("want Side.IsSell() to be %v but got %v", tt.want, got)
 			}
 		})

internal/mocks/mocks_gen.go

@@ -220,6 +220,44 @@ func (c *MockRecordFeesCall) DoAndReturn(f func() decimal.Decimal) *MockRecordFe
 	return c
 }
 
+// Kind mocks base method.
+func (m *MockRecord) Kind() internal.Kind {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Kind")
+	ret0, _ := ret[0].(internal.Kind)
+	return ret0
+}
+
+// Kind indicates an expected call of Kind.
+func (mr *MockRecordMockRecorder) Kind() *MockRecordKindCall {
+	mr.mock.ctrl.T.Helper()
+	call := mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Kind", reflect.TypeOf((*MockRecord)(nil).Kind))
+	return &MockRecordKindCall{Call: call}
+}
+
+// MockRecordKindCall wrap *gomock.Call
+type MockRecordKindCall struct {
+	*gomock.Call
+}
+
+// Return rewrite *gomock.Call.Return
+func (c *MockRecordKindCall) Return(arg0 internal.Kind) *MockRecordKindCall {
+	c.Call = c.Call.Return(arg0)
+	return c
+}
+
+// Do rewrite *gomock.Call.Do
+func (c *MockRecordKindCall) Do(f func() internal.Kind) *MockRecordKindCall {
+	c.Call = c.Call.Do(f)
+	return c
+}
+
+// DoAndReturn rewrite *gomock.Call.DoAndReturn
+func (c *MockRecordKindCall) DoAndReturn(f func() internal.Kind) *MockRecordKindCall {
+	c.Call = c.Call.DoAndReturn(f)
+	return c
+}
+
 // Nature mocks base method.
 func (m *MockRecord) Nature() internal.Nature {
 	m.ctrl.T.Helper()
@@ -334,44 +372,6 @@ func (c *MockRecordQuantityCall) DoAndReturn(f func() decimal.Decimal) *MockReco
 	return c
 }
 
-// Side mocks base method.
-func (m *MockRecord) Side() internal.Side {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Side")
-	ret0, _ := ret[0].(internal.Side)
-	return ret0
-}
-
-// Side indicates an expected call of Side.
-func (mr *MockRecordMockRecorder) Side() *MockRecordSideCall {
-	mr.mock.ctrl.T.Helper()
-	call := mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Side", reflect.TypeOf((*MockRecord)(nil).Side))
-	return &MockRecordSideCall{Call: call}
-}
-
-// MockRecordSideCall wrap *gomock.Call
-type MockRecordSideCall struct {
-	*gomock.Call
-}
-
-// Return rewrite *gomock.Call.Return
-func (c *MockRecordSideCall) Return(arg0 internal.Side) *MockRecordSideCall {
-	c.Call = c.Call.Return(arg0)
-	return c
-}
-
-// Do rewrite *gomock.Call.Do
-func (c *MockRecordSideCall) Do(f func() internal.Side) *MockRecordSideCall {
-	c.Call = c.Call.Do(f)
-	return c
-}
-
-// DoAndReturn rewrite *gomock.Call.DoAndReturn
-func (c *MockRecordSideCall) DoAndReturn(f func() internal.Side) *MockRecordSideCall {
-	c.Call = c.Call.DoAndReturn(f)
-	return c
-}
-
 // Symbol mocks base method.
 func (m *MockRecord) Symbol() string {
 	m.ctrl.T.Helper()

internal/report.go

@@ -16,7 +16,7 @@ type Record interface {
 	Nature() Nature
 	BrokerCountry() int64
 	AssetCountry() int64
-	Side() Side
+	Kind() Kind
 	Price() decimal.Decimal
 	Quantity() decimal.Decimal
 	Timestamp() time.Time
@@ -83,9 +83,9 @@ func BuildReport(ctx context.Context, reader RecordReader, writer ReportWriter,
 				return err
 			}
 
-			if rec.Side().IsBuy() {
+			if rec.Kind().Is(KindBuy) {
 				buysCount++
-			} else {
+			} else if rec.Kind().Is(KindSell) {
 				sellsCount++
 			}
 
@@ -108,23 +108,23 @@ func BuildReport(ctx context.Context, reader RecordReader, writer ReportWriter,
 
 // processRecord either adds buys to the queue or consumes buys from the queue when processing a
 // sell record.
-// Selectors are only applied for sells for performance reasons. It's much cheaper to just accumulate
-// buys and only actually inspect a record once a sell happens
+// Selectors are only applied on sells for performance reasons. It's much cheaper to just accumulate
+// buys and only actually inspect a record once a sell happens due to potential network requests to
 func processRecord(ctx context.Context, q *FillerQueue, rec Record, sel Selector, writer ReportWriter) error {
 	slog.Debug("Report: processing record",
 		slog.String("symbol", rec.Symbol()),
-		slog.String("side", rec.Side().String()),
+		slog.String("side", rec.Kind().String()),
 	)
 
-	switch rec.Side() {
-	case SideBuy:
+	switch rec.Kind() {
+	case KindBuy:
 		q.Push(NewFiller(rec))
 
-	case SideSell:
+	case KindSell:
 		if !sel(rec) {
 			slog.Debug("Report: skipping record",
 				slog.String("symbol", rec.Symbol()),
-				slog.String("side", rec.Side().String()),
+				slog.String("side", rec.Kind().String()),
 			)
 			return nil
 		}
@@ -168,8 +168,11 @@ func processRecord(ctx context.Context, q *FillerQueue, rec Record, sel Selector
 			}
 		}
 
+	case KindSplit:
+		q.AdjustForSplit(rec.Quantity())
+
 	default:
-		return fmt.Errorf("unknown side: %v", rec.Side())
+		return fmt.Errorf("unknown side: %v", rec.Kind())
 	}
 
 	return nil

internal/report_test.go

@@ -20,8 +20,8 @@ func TestBuildReport(t *testing.T) {
 
 	reader := mocks.NewMockRecordReader(ctrl)
 	records := []internal.Record{
-		mockRecord(ctrl, 20.0, 10.0, internal.SideBuy, now),
-		mockRecord(ctrl, 25.0, 10.0, internal.SideSell, now.Add(1)),
+		mockRecord(ctrl, 20.0, 10.0, internal.KindBuy, now),
+		mockRecord(ctrl, 25.0, 10.0, internal.KindSell, now.Add(1)),
 	}
 	reader.EXPECT().ReadRecord(gomock.Any()).DoAndReturn(func(ctx context.Context) (internal.Record, error) {
 		if len(records) > 0 {
@@ -49,14 +49,14 @@ func TestBuildReport(t *testing.T) {
 	}
 }
 
-func mockRecord(ctrl *gomock.Controller, price, quantity float64, side internal.Side, ts time.Time) *mocks.MockRecord {
+func mockRecord(ctrl *gomock.Controller, price, quantity float64, kind internal.Kind, ts time.Time) *mocks.MockRecord {
 	rec := mocks.NewMockRecord(ctrl)
 	rec.EXPECT().Symbol().Return("TEST").AnyTimes()
 	rec.EXPECT().BrokerCountry().Return(int64(countries.PT)).AnyTimes()
 	rec.EXPECT().AssetCountry().Return(int64(countries.USA)).AnyTimes()
 	rec.EXPECT().Price().Return(decimal.NewFromFloat(price)).AnyTimes()
 	rec.EXPECT().Quantity().Return(decimal.NewFromFloat(quantity)).AnyTimes()
-	rec.EXPECT().Side().Return(side).AnyTimes()
+	rec.EXPECT().Kind().Return(kind).AnyTimes()
 	rec.EXPECT().Timestamp().Return(ts).AnyTimes()
 	rec.EXPECT().Fees().Return(decimal.Decimal{}).AnyTimes()
 	rec.EXPECT().Taxes().Return(decimal.Decimal{}).AnyTimes()

internal/selectors_test.go

@@ -9,28 +9,28 @@ import (
 )
 
 type testRecord struct {
-	symbol       string
-	nature       internal.Nature
+	symbol        string
+	nature        internal.Nature
 	brokerCountry int64
-	assetCountry int64
-	side         internal.Side
-	price        decimal.Decimal
-	quantity     decimal.Decimal
-	timestamp    time.Time
-	fees         decimal.Decimal
-	taxes        decimal.Decimal
+	assetCountry  int64
+	side          internal.Kind
+	price         decimal.Decimal
+	quantity      decimal.Decimal
+	timestamp     time.Time
+	fees          decimal.Decimal
+	taxes         decimal.Decimal
 }
 
-func (m testRecord) Symbol() string                { return m.symbol }
-func (m testRecord) Nature() internal.Nature       { return m.nature }
-func (m testRecord) BrokerCountry() int64          { return m.brokerCountry }
-func (m testRecord) AssetCountry() int64           { return m.assetCountry }
-func (m testRecord) Side() internal.Side           { return m.side }
-func (m testRecord) Price() decimal.Decimal        { return m.price }
-func (m testRecord) Quantity() decimal.Decimal     { return m.quantity }
-func (m testRecord) Timestamp() time.Time          { return m.timestamp }
-func (m testRecord) Fees() decimal.Decimal         { return m.fees }
-func (m testRecord) Taxes() decimal.Decimal        { return m.taxes }
+func (m testRecord) Symbol() string            { return m.symbol }
+func (m testRecord) Nature() internal.Nature   { return m.nature }
+func (m testRecord) BrokerCountry() int64      { return m.brokerCountry }
+func (m testRecord) AssetCountry() int64       { return m.assetCountry }
+func (m testRecord) Kind() internal.Kind       { return m.side }
+func (m testRecord) Price() decimal.Decimal    { return m.price }
+func (m testRecord) Quantity() decimal.Decimal { return m.quantity }
+func (m testRecord) Timestamp() time.Time      { return m.timestamp }
+func (m testRecord) Fees() decimal.Decimal     { return m.fees }
+func (m testRecord) Taxes() decimal.Decimal    { return m.taxes }
 
 func TestAny(t *testing.T) {
 	selector := internal.Any()
@@ -43,9 +43,9 @@ func TestAny(t *testing.T) {
 		{
 			name: "returns true for any record",
 			record: testRecord{
-				symbol:        "AAPL",
-				nature:        internal.NatureG01,
-				assetCountry:  1,
+				symbol:       "AAPL",
+				nature:       internal.NatureG01,
+				assetCountry: 1,
 			},
 			want: true,
 		},
@@ -59,7 +59,7 @@ func TestAny(t *testing.T) {
 			want: true,
 		},
 		{
-			name: "returns true for empty record",
+			name:   "returns true for empty record",
 			record: testRecord{},
 			want:   true,
 		},
@@ -77,10 +77,10 @@ func TestAny(t *testing.T) {
 
 func TestOnlyNature(t *testing.T) {
 	tests := []struct {
-		name     string
-		nature   internal.Nature
-		record   internal.Record
-		want     bool
+		name   string
+		nature internal.Nature
+		record internal.Record
+		want   bool
 	}{
 		{
 			name:   "matches G01 nature",
@@ -133,10 +133,10 @@ func TestOnlyNature(t *testing.T) {
 
 func TestOnlyAssetCountry(t *testing.T) {
 	tests := []struct {
-		name         string
-		country      int64
-		record       internal.Record
-		want         bool
+		name    string
+		country int64
+		record  internal.Record
+		want    bool
 	}{
 		{
 			name:    "matches asset country",

internal/side.go

@@ -1,30 +0,0 @@
-package internal
-
-type Side uint
-
-const (
-	SideUnknown Side = iota
-	SideBuy
-	SideSell
-)
-
-func (d Side) String() string {
-	switch d {
-	case SideBuy:
-		return "buy"
-	case SideSell:
-		return "sell"
-	default:
-		return "unknown"
-	}
-}
-
-// IsBuy returns true if the s == SideBuy
-func (d Side) IsBuy() bool {
-	return d == SideBuy
-}
-
-// IsSell returns true if the s == SideSell
-func (d Side) IsSell() bool {
-	return d == SideSell
-}

internal/trading212/record.go

@@ -18,7 +18,7 @@ import (
 type Record struct {
 	symbol    string
 	timestamp time.Time
-	side      internal.Side
+	kind      internal.Kind
 	quantity  decimal.Decimal
 	price     decimal.Decimal
 	fees      decimal.Decimal
@@ -44,8 +44,8 @@ func (r Record) AssetCountry() int64 {
 	return int64(countries.ByName(r.Symbol()[:2]).Info().Code)
 }
 
-func (r Record) Side() internal.Side {
-	return r.side
+func (r Record) Kind() internal.Kind {
+	return r.kind
 }
 
 func (r Record) Quantity() decimal.Decimal {
@@ -81,29 +81,26 @@ func NewRecordReader(r io.Reader, f *internal.OpenFIGI) *RecordReader {
 }
 
 const (
-	MarketBuy  = "market buy"
-	MarketSell = "market sell"
-	LimitBuy   = "limit buy"
-	LimitSell  = "limit sell"
+	MarketBuy        = "market buy"
+	MarketSell       = "market sell"
+	LimitBuy         = "limit buy"
+	LimitSell        = "limit sell"
+	StockSplitOpen   = "stock split open"
+	StockSplitClose  = "stock split close"
+	StokDistribution = "stock distribution"
 )
 
 func (rr RecordReader) ReadRecord(ctx context.Context) (internal.Record, error) {
+	var splitRec *splitRecord
+
 	for {
 		raw, err := rr.reader.Read()
 		if err != nil {
 			return Record{}, fmt.Errorf("read record: %w", err)
 		}
 
-		var side internal.Side
-		switch strings.ToLower(raw[0]) {
-		case MarketBuy, LimitBuy:
-			side = internal.SideBuy
-		case MarketSell, LimitSell:
-			side = internal.SideSell
-		case "action", "stock split open", "stock split close":
+		if strings.ToLower(raw[0]) == "action" {
 			continue
-		default:
-			return Record{}, fmt.Errorf("parse record type: %s", raw[0])
 		}
 
 		qant, err := parseDecimal(raw[6])
@@ -136,9 +133,50 @@ func (rr RecordReader) ReadRecord(ctx context.Context) (internal.Record, error)
 			return Record{}, fmt.Errorf("parse record french transaction tax: %w", err)
 		}
 
+		var kind internal.Kind
+		switch strings.ToLower(raw[0]) {
+		case MarketBuy, LimitBuy:
+			kind = internal.KindBuy
+		case MarketSell, LimitSell:
+			kind = internal.KindSell
+		case StockSplitOpen:
+			if splitRec != nil {
+				return nil, fmt.Errorf("split already open")
+			}
+
+			splitRec = &splitRecord{
+				Record: Record{
+					symbol:       raw[2],
+					kind:         internal.KindSplit,
+					quantity:     qant,
+					price:        price,
+					fees:         conversionFee,
+					taxes:        stampDutyTax.Add(frenchTxTax),
+					timestamp:    ts,
+					natureGetter: figiNatureGetter(ctx, rr.figi, raw[2]),
+				},
+			}
+
+			continue
+
+		case StockSplitClose:
+			if splitRec == nil {
+				return nil, fmt.Errorf("missing split open")
+			}
+			splitRec.ratio = splitRec.Record.Quantity().Div(qant)
+			return splitRec, nil
+
+		case StokDistribution:
+			slog.Warn("Found stock distribution but can't handle it")
+			continue
+
+		default:
+			return Record{}, fmt.Errorf("parse record type: %s", raw[0])
+		}
+
 		return Record{
 			symbol:       raw[2],
-			side:         side,
+			kind:         kind,
 			quantity:     qant,
 			price:        price,
 			fees:         conversionFee,
@@ -185,3 +223,13 @@ func parseOptionalDecimal(s string) (decimal.Decimal, error) {
 
 	return parseDecimal(s)
 }
+
+type splitRecord struct {
+	Record
+
+	ratio decimal.Decimal
+}
+
+func (sr splitRecord) Quantity() decimal.Decimal {
+	return sr.ratio
+}

internal/trading212/record_test.go

@@ -30,7 +30,7 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 			r:    bytes.NewBufferString(`Market buy,2025-07-03 10:44:29,XX1234567890,ABXY,"Aspargus Broccoli",EOF987654321,2.4387014200,7.3690000000,USD,1.17995999,,"EUR",15.25,"EUR",0.25,"EUR",0.02,"EUR",,`),
 			want: Record{
 				symbol:       "XX1234567890",
-				side:         internal.SideBuy,
+				kind:         internal.KindBuy,
 				quantity:     ShouldParseDecimal(t, "2.4387014200"),
 				price:        ShouldParseDecimal(t, "7.3690000000"),
 				timestamp:    time.Date(2025, 7, 3, 10, 44, 29, 0, time.UTC),
@@ -44,7 +44,7 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 			r:    bytes.NewBufferString(`Market sell,2025-08-04 11:45:30,XX1234567890,ABXY,"Aspargus Broccoli",EOF987654321,2.4387014200,7.9999999999,USD,1.17995999,,"EUR",15.25,"EUR",,,0.02,"EUR",0.1,"EUR"`),
 			want: Record{
 				symbol:       "XX1234567890",
-				side:         internal.SideSell,
+				kind:         internal.KindSell,
 				quantity:     ShouldParseDecimal(t, "2.4387014200"),
 				price:        ShouldParseDecimal(t, "7.9999999999"),
 				timestamp:    time.Date(2025, 8, 4, 11, 45, 30, 0, time.UTC),
@@ -123,8 +123,8 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 				t.Fatalf("want symbol %v but got %v", tt.want.symbol, got.Symbol())
 			}
 
-			if got.Side() != tt.want.side {
-				t.Fatalf("want side %v but got %v", tt.want.side, got.Side())
+			if got.Kind() != tt.want.kind {
+				t.Fatalf("want side %v but got %v", tt.want.kind, got.Kind())
 			}
 
 			if got.Price().Cmp(tt.want.price) != 0 {
@@ -154,6 +154,70 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 	}
 }
 
+func TestRecordReader_ReadRecord_Split(t *testing.T) {
+	// open row has the NEW (post-split) position: more shares at lower price
+	// close row has the OLD (pre-split) position: fewer shares at higher price
+	// ratio = openQty / closeQty = 0.5 / 0.1 = 5 (a 5:1 split)
+	splitOpen  := `Stock split open,2025-06-03 05:34:16,XX1234567890,ABXY,"Aspargus Broccoli",EOF111111111,0.5000000000,20.0000000000,EUR,1.00000000,,,10.00,"EUR",,,,,,`
+	splitClose := `Stock split close,2025-06-03 05:34:16,XX1234567890,ABXY,"Aspargus Broccoli",EOF222222222,0.1000000000,100.0000000000,EUR,1.00000000,0.00,"EUR",10.00,"EUR",,,,,,`
+
+	t.Run("well-formed split pair returns split record with correct ratio", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitOpen+"\n"+splitClose),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		got, err := rr.ReadRecord(t.Context())
+		if err != nil {
+			t.Fatalf("ReadRecord() failed: %v", err)
+		}
+
+		if got.Kind() != internal.KindSplit {
+			t.Errorf("want kind %v but got %v", internal.KindSplit, got.Kind())
+		}
+		if got.Symbol() != "NO0013536151" {
+			t.Errorf("want symbol NO0013536151 but got %v", got.Symbol())
+		}
+
+		wantTimestamp := time.Date(2025, 6, 3, 5, 34, 16, 0, time.UTC)
+		if !got.Timestamp().Equal(wantTimestamp) {
+			t.Errorf("want timestamp %v but got %v", wantTimestamp, got.Timestamp())
+		}
+
+		// ratio = openQty / closeQty = 0.1245045 / 0.0249009 ≈ 5
+		openQty := ShouldParseDecimal(t, "0.1245045000")
+		closeQty := ShouldParseDecimal(t, "0.0249009000")
+		wantRatio := openQty.Div(closeQty)
+		if !got.Quantity().Equal(wantRatio) {
+			t.Errorf("want ratio %v but got %v", wantRatio, got.Quantity())
+		}
+	})
+
+	t.Run("close without prior open errors", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitClose),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		_, err := rr.ReadRecord(t.Context())
+		if err == nil {
+			t.Fatal("expected error but got none")
+		}
+	})
+
+	t.Run("two opens without close errors", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitOpen+"\n"+splitOpen),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		_, err := rr.ReadRecord(t.Context())
+		if err == nil {
+			t.Fatal("expected error but got none")
+		}
+	})
+}
+
 func Test_figiNatureGetter(t *testing.T) {
 	tests := []struct {
 		name string // description of this test case