diff --git a/engine/statmetrics.go b/engine/statmetrics.go
index ee91570a2..7904d55a0 100644
--- a/engine/statmetrics.go
+++ b/engine/statmetrics.go
@@ -33,24 +33,34 @@ import (
 	"github.com/ericlagergren/decimal"
 )
 
+type metricConstructor func(uint64, string, []string) StatMetric
+type metricConstructorErr func(uint64, string, []string) (StatMetric, error)
+
+// withErrReturn wraps a constructor to return an error (always nil).
+func withErrReturn(fn metricConstructor) metricConstructorErr {
+	return func(minItems uint64, extraParams string, filterIDs []string) (StatMetric, error) {
+		return fn(minItems, extraParams, filterIDs), nil
+	}
+}
+
 // NewStatMetric instantiates the StatMetric
 // cfg serves as general purpose container to pass config options to metric
 func NewStatMetric(metricID string, minItems uint64, filterIDs []string) (sm StatMetric, err error) {
-	metrics := map[string]func(uint64, string, []string) StatMetric{
-		utils.MetaASR:      NewASR,
-		utils.MetaACD:      NewACD,
-		utils.MetaTCD:      NewTCD,
-		utils.MetaACC:      NewACC,
-		utils.MetaTCC:      NewTCC,
-		utils.MetaPDD:      NewPDD,
-		utils.MetaDDC:      NewDDC,
-		utils.MetaSum:      NewStatSum,
-		utils.MetaAverage:  NewStatAverage,
-		utils.MetaDistinct: NewStatDistinct,
-		utils.MetaHighest:  NewStatHighest,
-		utils.MetaLowest:   NewStatLowest,
-		utils.MetaREPSC:    NewStatREPSC,
-		utils.MetaREPFC:    NewStatREPFC,
+	metrics := map[string]metricConstructorErr{
+		utils.MetaASR:      withErrReturn(NewASR),
+		utils.MetaACD:      withErrReturn(NewACD),
+		utils.MetaTCD:      withErrReturn(NewTCD),
+		utils.MetaACC:      withErrReturn(NewACC),
+		utils.MetaTCC:      withErrReturn(NewTCC),
+		utils.MetaPDD:      withErrReturn(NewPDD),
+		utils.MetaDDC:      withErrReturn(NewDDC),
+		utils.MetaSum:      NewStatSum, // Already returns (StatMetric, error)
+		utils.MetaAverage:  withErrReturn(NewStatAverage),
+		utils.MetaDistinct: withErrReturn(NewStatDistinct),
+		utils.MetaHighest:  withErrReturn(NewStatHighest),
+		utils.MetaLowest:   withErrReturn(NewStatLowest),
+		utils.MetaREPSC:    withErrReturn(NewStatREPSC),
+		utils.MetaREPFC:    withErrReturn(NewStatREPFC),
 	}
 	// split the metricID
 	// in case of *sum we have *sum#~*req.FieldName
@@ -62,7 +72,7 @@ func NewStatMetric(metricID string, minItems uint64, filterIDs []string) (sm Sta
 	if len(metricSplit[1:]) > 0 {
 		extraParams = metricSplit[1]
 	}
-	return metrics[metricSplit[0]](minItems, extraParams, filterIDs), nil
+	return metrics[metricSplit[0]](minItems, extraParams, filterIDs)
 }
 
 // StatMetric is the interface which a metric should implement
@@ -771,12 +781,15 @@ func (m *Metric) Equal(v *Metric) bool {
 	return true
 }
 
-func NewStatSum(minItems uint64, fieldName string, filterIDs []string) StatMetric {
-	flds, _ := utils.NewRSRParsers(fieldName, utils.InfieldSep)
+func NewStatSum(minItems uint64, fieldName string, filterIDs []string) (StatMetric, error) {
+	flds, err := utils.NewRSRParsers(fieldName, utils.InfieldSep)
+	if err != nil {
+		return nil, err
+	}
 	return &StatSum{
 		Metric: NewMetric(minItems, filterIDs),
 		Fields: flds,
-	}
+	}, nil
 }
 
 type StatSum struct {
diff --git a/engine/statmetrics_test.go b/engine/statmetrics_test.go
index f157615ef..81e5c2ad9 100644
--- a/engine/statmetrics_test.go
+++ b/engine/statmetrics_test.go
@@ -2101,7 +2101,10 @@ func TestDDCGetCompressFactor(t *testing.T) {
 }
 
 func TestStatSumGetFloat64Value(t *testing.T) {
-	statSum := NewStatSum(2, "~*opts.*cost", nil)
+	statSum, err := NewStatSum(2, "~*opts.*cost", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
 	ev := &utils.CGREvent{ID: "EVENT_1",
 		APIOpts: map[string]any{
 			utils.MetaDestination: "1002",
@@ -2165,7 +2168,10 @@ func TestStatSumGetFloat64Value(t *testing.T) {
 }
 
 func TestStatSumGetStringValue(t *testing.T) {
-	statSum := NewStatSum(2, "~*opts.*cost", nil)
+	statSum, err := NewStatSum(2, "~*opts.*cost", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
 	ev := &utils.CGREvent{ID: "EVENT_1",
 		APIOpts: map[string]any{
 			utils.MetaDestination: "1002",
@@ -2210,7 +2216,10 @@ func TestStatSumGetStringValue(t *testing.T) {
 }
 
 func TestStatSumGetStringValue2(t *testing.T) {
-	statSum := NewStatSum(2, "~*opts.*cost", nil)
+	statSum, err := NewStatSum(2, "~*opts.*cost", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
 	ev1 := &utils.CGREvent{ID: "EVENT_1",
 		APIOpts: map[string]any{utils.MetaCost: 12.3}}
 	if err := statSum.AddEvent(ev1.ID, utils.MapStorage{utils.MetaOpts: ev1.APIOpts}); err != nil {
@@ -2383,7 +2392,10 @@ func TestStatSumGetCompressFactor(t *testing.T) {
 		"EVENT_1": 1,
 		"EVENT_2": 1,
 	}
-	sum := NewStatSum(2, "~*opts.*cost", nil)
+	sum, err := NewStatSum(2, "~*opts.*cost", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
 	ev := &utils.CGREvent{ID: "EVENT_1",
 		APIOpts: map[string]any{utils.MetaCost: 18.2}}
 	ev2 := &utils.CGREvent{ID: "EVENT_2",
@@ -3034,7 +3046,10 @@ func TestDCCMarshal(t *testing.T) {
 }
 
 func TestStatSumMarshal(t *testing.T) {
-	statSum := NewStatSum(2, "~*opts.*cost", nil)
+	statSum, err := NewStatSum(2, "~*opts.*cost", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
 	ev := &utils.CGREvent{ID: "EVENT_1",
 		APIOpts: map[string]any{
 			utils.MetaDestination: "1002",
diff --git a/engine/stats_test.go b/engine/stats_test.go
index b2e115491..dd9dfa3f8 100644
--- a/engine/stats_test.go
+++ b/engine/stats_test.go
@@ -32,6 +32,14 @@ import (
 	"github.com/cgrates/cgrates/utils"
 )
 
+func mustNewStatSum(minItems uint64, fieldName string, filterIDs []string) StatMetric {
+	sum, err := NewStatSum(minItems, fieldName, filterIDs)
+	if err != nil {
+		panic(err)
+	}
+	return sum
+}
+
 var (
 	testStatsPrfs = []*StatQueueProfile{
 		{
@@ -104,7 +112,7 @@ var (
 			ID:     "StatQueueProfile1",
 			sqPrfl: testStatsPrfs[0],
 			SQMetrics: map[string]StatMetric{
-				utils.MetaSum: NewStatSum(1, "~*req.Usage", nil),
+				utils.MetaSum: mustNewStatSum(1, "~*req.Usage", nil),
 			},
 		},
 		{
@@ -112,7 +120,7 @@ var (
 			ID:     "StatQueueProfile2",
 			sqPrfl: testStatsPrfs[1],
 			SQMetrics: map[string]StatMetric{
-				utils.MetaSum: NewStatSum(1, "~*req.Usage", nil),
+				utils.MetaSum: mustNewStatSum(1, "~*req.Usage", nil),
 			},
 		},
 		{
@@ -120,7 +128,7 @@ var (
 			ID:     "StatQueueProfilePrefix",
 			sqPrfl: testStatsPrfs[2],
 			SQMetrics: map[string]StatMetric{
-				utils.MetaSum: NewStatSum(1, "~*req.Usage", nil),
+				utils.MetaSum: mustNewStatSum(1, "~*req.Usage", nil),
 			},
 		},
 	}