diff --git a/pkg/indicator/v2/boll.go b/pkg/indicator/v2/boll.go
index 260d9f4eb..9feda9f52 100644
--- a/pkg/indicator/v2/boll.go
+++ b/pkg/indicator/v2/boll.go
@@ -55,3 +55,7 @@ func (s *BOLLStream) Calculate(v float64) float64 {
 	band := stdDev * s.k
 	return band
 }
+
+func (s *BOLLStream) Truncate() {
+	s.Slice = generalTruncate(s.Slice)
+}
diff --git a/pkg/indicator/v2/rma.go b/pkg/indicator/v2/rma.go
index b943cf6f8..828ee9224 100644
--- a/pkg/indicator/v2/rma.go
+++ b/pkg/indicator/v2/rma.go
@@ -5,7 +5,6 @@ import (
 )
 
 const MaxNumOfRMA = 1000
-const MaxNumOfRMATruncateSize = 500
 
 type RMAStream struct {
 	// embedded structs
@@ -51,9 +50,7 @@ func (s *RMAStream) Calculate(x float64) float64 {
 }
 
 func (s *RMAStream) Truncate() {
-	if len(s.Slice) > MaxNumOfRMA {
-		s.Slice = s.Slice[MaxNumOfRMATruncateSize-1:]
-	}
+	s.Slice = generalTruncate(s.Slice)
 }
 
 func checkWindow(window int) {
diff --git a/pkg/indicator/v2/sma.go b/pkg/indicator/v2/sma.go
index 5afd4f825..0902db5a7 100644
--- a/pkg/indicator/v2/sma.go
+++ b/pkg/indicator/v2/sma.go
@@ -4,8 +4,6 @@ import (
 	"github.com/c9s/bbgo/pkg/types"
 )
 
-const MaxNumOfSMA = 5_000
-
 type SMAStream struct {
 	*types.Float64Series
 	window    int
@@ -29,5 +27,5 @@ func (s *SMAStream) Calculate(v float64) float64 {
 }
 
 func (s *SMAStream) Truncate() {
-	s.Slice = s.Slice.Truncate(MaxNumOfSMA)
+	s.Slice = generalTruncate(s.Slice)
 }
diff --git a/pkg/indicator/v2/stddev.go b/pkg/indicator/v2/stddev.go
index a9e94974d..223d8e7f2 100644
--- a/pkg/indicator/v2/stddev.go
+++ b/pkg/indicator/v2/stddev.go
@@ -26,3 +26,7 @@ func (s *StdDevStream) Calculate(x float64) float64 {
 	var std = s.rawValues.Stdev()
 	return std
 }
+
+func (s *StdDevStream) Truncate() {
+	s.Slice = generalTruncate(s.Slice)
+}
diff --git a/pkg/indicator/v2/truncate.go b/pkg/indicator/v2/truncate.go
new file mode 100644
index 000000000..9178c6b09
--- /dev/null
+++ b/pkg/indicator/v2/truncate.go
@@ -0,0 +1,16 @@
+package indicatorv2
+
+// MaxSliceSize is the maximum slice size
+// byte size = 8 * 5000 = 40KB per slice
+const MaxSliceSize = 5000
+
+// TruncateSize is the truncate size for the slice per truncate call
+const TruncateSize = 1000
+
+func generalTruncate(slice []float64) []float64 {
+	if len(slice) < MaxSliceSize {
+		return slice
+	}
+
+	return slice[TruncateSize-1:]
+}