diff --git a/src/Npgsql/Internal/Converters/Primitive/NumericConverters.cs b/src/Npgsql/Internal/Converters/Primitive/NumericConverters.cs
index c14a00b608..714d3c49d4 100644
--- a/src/Npgsql/Internal/Converters/Primitive/NumericConverters.cs
+++ b/src/Npgsql/Internal/Converters/Primitive/NumericConverters.cs
@@ -166,7 +166,7 @@ public static async ValueTask<PgNumeric> ReadAsync(PgReader reader, ArraySegment
         var sign = reader.ReadInt16();
         var scale = reader.ReadInt16();
         var array = digits.Array!;
-        for (var i = digits.Offset; i < array.Length; i++)
+        for (var i = digits.Offset; i < digits.Offset + digits.Count; i++)
         {
             if (reader.ShouldBuffer(sizeof(short)))
                 await reader.BufferAsync(sizeof(short), cancellationToken).ConfigureAwait(false);
diff --git a/test/Npgsql.Tests/Types/NumericTests.cs b/test/Npgsql.Tests/Types/NumericTests.cs
index 20eed3fa04..439d651559 100644
--- a/test/Npgsql.Tests/Types/NumericTests.cs
+++ b/test/Npgsql.Tests/Types/NumericTests.cs
@@ -212,4 +212,18 @@ public async Task NumericZero_WithScale()
 
         Assert.That(value.Scale, Is.EqualTo(2));
     }
+
+    [Test, IssueLink("https://github.com/npgsql/npgsql/issues/6383")]
+    public async Task Read_Many_Numerics_As_BigInteger([Values(CommandBehavior.Default, CommandBehavior.SequentialAccess)] CommandBehavior behavior)
+    {
+        await using var conn = await OpenConnectionAsync();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT 1234567890::numeric FROM generate_series(1, 8000)";
+
+        await using var reader = await cmd.ExecuteReaderAsync(behavior);
+        while (await reader.ReadAsync())
+        {
+            Assert.DoesNotThrowAsync(async () => await reader.GetFieldValueAsync<BigInteger>(0));
+        }
+    }
 }