diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5aeafc..c460b96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@
 ### New in `sym`
 
 - Mathematical symbols
+  - `union.serif`: ∪︀
+  - `union.sq.serif`: ⊔︀
+  - `inter.serif`: ∩︀
+  - `inter.sq.serif`: ⊓︀
   - `gt.double.nested`: ⪢
   - `lt.double.nested`: ⪡
   - `gt.arc` ⪧
diff --git a/src/modules/sym.txt b/src/modules/sym.txt
index eb79e8a..1e28454 100644
--- a/src/modules/sym.txt
+++ b/src/modules/sym.txt
@@ -461,6 +461,7 @@ supset ⊃
   .tilde ⫈
   .times ⫂
 union ∪
+  .serif ∪\vs{1}
   .arrow ⊌
   .big ⋃
   .dot ⊍
@@ -471,14 +472,17 @@ union ∪
   .plus ⊎
   .plus.big ⨄
   .sq ⊔
+  .sq.serif ⊔\vs{1}
   .sq.big ⨆
   .sq.double ⩏
 inter ∩
+  .serif ∩\vs{1}
   .and ⩄
   .big ⋂
   .dot ⩀
   .double ⋒
   .sq ⊓
+  .sq.serif ⊓\vs{1}
   .sq.big ⨅
   .sq.double ⩎