diff --git a/extensions/Prefixes.md b/extensions/Prefixes.md
index 48fe34b4cd..3cd108eb89 100644
--- a/extensions/Prefixes.md
+++ b/extensions/Prefixes.md
@@ -14,6 +14,7 @@ The following extension prefixes are reserved:
 * `MSFT` - Microsoft
 * `NV` - NVIDIA Corporation
 * `OWLII` - Owlii
+* `S8S` - Soft8Soft
 * `WEB3D` - Web3D Consortium
 
 To request a prefix, submit a [GitHub issue](https://github.com/KhronosGroup/glTF/issues/new) with the name of the requested prefix and the vendor that will be using it.  Assign the `extension` label to the issue.