diff --git a/internal/achx/trace.go b/internal/achx/trace.go
index 90d6ebce..a438e278 100644
--- a/internal/achx/trace.go
+++ b/internal/achx/trace.go
@@ -5,34 +5,43 @@
 package achx
 
 import (
+	"crypto/rand"
 	"fmt"
-	"math/rand"
-	"time"
+	"math/big"
+	"strconv"
 	"unicode/utf8"
-)
 
-var (
-	traceNumberSource = rand.NewSource(time.Now().Unix())
+	"github.com/moov-io/ach"
+	"github.com/pkg/errors"
 )
 
 // TraceNumber returns a trace number from a given routing number
 // and uses a hidden random generator. These values are not expected
 // to be cryptographically secure.
-func TraceNumber(routingNumber string) string {
-	v := fmt.Sprintf("%s%d", ABA8(routingNumber), traceNumberSource.Int63())
+//
+// We decided not to increment trace numbers from a shared counter because
+// it will create a lot of "NNNNN00001" trace numbers that are duplicated
+// and hard to uniquely identify a Transfer.
+func TraceNumber(routingNumber string) (string, error) {
+	n, err := rand.Int(rand.Reader, big.NewInt(1e15))
+	if err != nil {
+		return "", errors.Wrap(err, "ERROR creating trace number")
+	}
+	v := fmt.Sprintf("%s%s", ABA8(routingNumber), n.String())
 	if utf8.RuneCountInString(v) > 15 {
-		return v[:15]
+		return v[:15], nil
 	}
-	return v
+	return v, nil
 }
 
 // ABA8 returns the first 8 digits of an ABA routing number.
 // If the input is invalid then an empty string is returned.
 func ABA8(rtn string) string {
-	if n := utf8.RuneCountInString(rtn); n == 10 {
+	n := utf8.RuneCountInString(rtn)
+	if n == 10 {
 		return rtn[1:9] // ACH server will prefix with space, 0, or 1
 	}
-	if n := utf8.RuneCountInString(rtn); n != 8 && n != 9 {
+	if n != 8 && n != 9 {
 		return ""
 	}
 	return rtn[:8]
@@ -41,10 +50,14 @@ func ABA8(rtn string) string {
 // ABACheckDigit returns the last digit of an ABA routing number.
 // If the input is invalid then an empty string is returned.
 func ABACheckDigit(rtn string) string {
-	if n := utf8.RuneCountInString(rtn); n == 10 {
+	n := utf8.RuneCountInString(rtn)
+	if n == 10 {
 		return rtn[9:] // ACH server will prefix with space, 0, or 1
 	}
-	if n := utf8.RuneCountInString(rtn); n != 8 && n != 9 {
+	if n == 8 {
+		return strconv.Itoa(ach.CalculateCheckDigit(rtn))
+	}
+	if n != 8 && n != 9 {
 		return ""
 	}
 	return rtn[8:9]
diff --git a/internal/achx/trace_test.go b/internal/achx/trace_test.go
index 854de4e9..3e31457c 100644
--- a/internal/achx/trace_test.go
+++ b/internal/achx/trace_test.go
@@ -6,28 +6,34 @@ package achx
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestTrace__ABA(t *testing.T) {
-	routingNumber := "231380104"
-	if v := ABA8(routingNumber); v != "23138010" {
-		t.Errorf("got %s", v)
-	}
-	if v := ABACheckDigit(routingNumber); v != "4" {
-		t.Errorf("got %s", v)
-	}
+	// 9 digits
+	require.Equal(t, "23138010", ABA8("231380104"))
+	require.Equal(t, "4", ABACheckDigit("231380104"))
 
 	// 10 digit from ACH server
-	if v := ABA8("0123456789"); v != "12345678" {
-		t.Errorf("got %s", v)
-	}
-	if v := ABACheckDigit("0123456789"); v != "9" {
-		t.Errorf("got %s", v)
-	}
+	require.Equal(t, "12345678", ABA8("0123456789"))
+	require.Equal(t, "9", ABACheckDigit("0123456789"))
+
+	// 8 digits
+	require.Equal(t, "12345678", ABA8("12345678"))
+	require.Equal(t, "0", ABACheckDigit("12345678"))
+
+	// short
+	require.Equal(t, "", ABA8("1234"))
+	require.Equal(t, "", ABACheckDigit("1234"))
+	require.Equal(t, "", ABA8(""))
+	require.Equal(t, "", ABACheckDigit(""))
 }
 
 func TestTraceNumber(t *testing.T) {
-	if v := TraceNumber("121042882"); v == "" {
-		t.Error("empty trace number")
+	for i := 0; i < 10000; i++ {
+		trace, err := TraceNumber("121042882")
+		require.NoError(t, err)
+		require.NotEmpty(t, trace)
 	}
 }
diff --git a/pkg/response/entry_transformer.go b/pkg/response/entry_transformer.go
index 4938abd5..acea84a7 100644
--- a/pkg/response/entry_transformer.go
+++ b/pkg/response/entry_transformer.go
@@ -56,9 +56,14 @@ func (t *CorrectionTransformer) MorphEntry(fh ach.FileHeader, ed *ach.EntryDetai
 	out.IndividualName = ed.IndividualName
 	out.DiscretionaryData = ed.DiscretionaryData
 	out.AddendaRecordIndicator = 1
-	out.TraceNumber = achx.TraceNumber(fh.ImmediateDestination)
 	out.Category = ach.CategoryNOC
 
+	if trace, err := achx.TraceNumber(ed.RDFIIdentificationField()); err != nil {
+		return out, fmt.Errorf("generating trace number: %w", err)
+	} else {
+		out.TraceNumber = trace
+	}
+
 	// Create the NOC addenda
 	addenda98 := ach.NewAddenda98()
 	addenda98.ChangeCode = action.Correction.Code
@@ -115,9 +120,14 @@ func (t *ReturnTransformer) MorphEntry(fh ach.FileHeader, ed *ach.EntryDetail, a
 	out.IndividualName = ed.IndividualName
 	out.DiscretionaryData = ed.DiscretionaryData
 	out.AddendaRecordIndicator = 1
-	out.TraceNumber = achx.TraceNumber(fh.ImmediateDestination)
 	out.Category = ach.CategoryReturn
 
+	if trace, err := achx.TraceNumber(ed.RDFIIdentificationField()); err != nil {
+		return out, fmt.Errorf("generating trace number: %w", err)
+	} else {
+		out.TraceNumber = trace
+	}
+
 	// Create the Return addenda
 	addenda99 := ach.NewAddenda99()
 	addenda99.ReturnCode = action.Return.Code