diff --git a/src/statmodels.jl b/src/statmodels.jl
index b487a30e..11fc136d 100644
--- a/src/statmodels.jl
+++ b/src/statmodels.jl
@@ -63,7 +63,7 @@ show(io::IO, n::NoQuote) = print(io, n.s)
 
 ## coefficient tables with specialized show method
 
-mutable struct CoefTable
+struct CoefTable
     cols::Vector
     colnms::Vector
     rownms::Vector