diff --git a/fragment.go b/fragment.go
index 2b2925e16..1718d4acb 100644
--- a/fragment.go
+++ b/fragment.go
@@ -1733,12 +1733,15 @@ func (f *fragment) bulkImportMutex(rowIDs, columnIDs []uint64) error {
 
 // importValue bulk imports a set of range-encoded values.
 func (f *fragment) importValue(columnIDs, values []uint64, bitDepth uint, clear bool) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
 	// Verify that there are an equal number of column ids and values.
 	if len(columnIDs) != len(values) {
 		return fmt.Errorf("mismatch of column/value len: %d != %d", len(columnIDs), len(values))
 	}
 	var toSet, toClear []uint64
-	f.mu.RLock()
+
 	smallWrite := false
 	if len(columnIDs)*int(bitDepth+1)+f.opN < f.MaxOpN {
 		smallWrite = true
@@ -1751,14 +1754,11 @@ func (f *fragment) importValue(columnIDs, values []uint64, bitDepth uint, clear
 		toSet = make([]uint64, 0, len(columnIDs)*int(bitDepth+1)*(5/8))
 		toClear = make([]uint64, 0, len(columnIDs)*int(bitDepth+1)*(5/8))
 	}
-	f.mu.RUnlock()
 
 	if !smallWrite {
-		f.mu.Lock()
-		defer f.mu.Unlock()
-
 		f.storage.OpWriter = nil
 	}
+
 	// Process every value.
 	// If an error occurs then reopen the storage.
 	if err := func() (err error) {
diff --git a/fragment_internal_test.go b/fragment_internal_test.go
index b726d4fe5..71d3b5ebe 100644
--- a/fragment_internal_test.go
+++ b/fragment_internal_test.go
@@ -3024,3 +3024,24 @@ func TestSmallImportRestart(t *testing.T) {
 		t.Errorf("row 1 should be [1], but got %v", r1)
 	}
 }
+
+func TestImportValueConcurrent(t *testing.T) {
+	f := mustOpenFragment("i", "f", viewBSIGroupPrefix+"foo", 0, "none")
+	eg := &errgroup.Group{}
+	for i := 0; i < 4; i++ {
+		i := i
+		eg.Go(func() error {
+			for j := uint64(0); j < 10; j++ {
+				err := f.importValue([]uint64{j}, []uint64{uint64(rand.Int63n(1000))}, 10, i%2 == 0)
+				if err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+	}
+	err := eg.Wait()
+	if err != nil {
+		t.Fatalf("concurrently importing values: %v", err)
+	}
+}