diff --git a/packages/SwingSet/src/kernel/vat-loader/manager-subprocess-xsnap.js b/packages/SwingSet/src/kernel/vat-loader/manager-subprocess-xsnap.js
index aec26383cce..95e108af0d4 100644
--- a/packages/SwingSet/src/kernel/vat-loader/manager-subprocess-xsnap.js
+++ b/packages/SwingSet/src/kernel/vat-loader/manager-subprocess-xsnap.js
@@ -252,7 +252,7 @@ export function makeXsSubprocessFactory({
         const uncompressedSizeDelta =
           uncompressedSizeLoaded &&
           metrics.uncompressedSize - uncompressedSizeLoaded;
-        uncompressedSizeLoaded = snapshotResults.uncompressedSize;
+        uncompressedSizeLoaded = results.uncompressedSize;
         kernelSlog.write({
           type: 'heap-snapshot-save',
           vatID,