diff --git a/lib/spack/spack/compilers/xl.py b/lib/spack/spack/compilers/xl.py
index 8fda5cb536..1e5ca52d33 100644
--- a/lib/spack/spack/compilers/xl.py
+++ b/lib/spack/spack/compilers/xl.py
@@ -112,6 +112,12 @@ def fc_version(cls, fc):
            older version of AIX and linux on power.
         """
         fver = get_compiler_version(fc, '-qversion', r'([0-9]?[0-9]\.[0-9])')
+        if fver >= 16:
+            """Starting with version 16.1, the XL C and Fortran compilers
+               have the same version.  So no need to downgrade the Fortran
+               compiler version to match that of the C compiler version.
+            """
+            return str(fver)
         cver = float(fver) - 2
         if cver < 10:
             cver = cver - 0.1
diff --git a/lib/spack/spack/compilers/xl_r.py b/lib/spack/spack/compilers/xl_r.py
index 1afaa45e63..717d631873 100644
--- a/lib/spack/spack/compilers/xl_r.py
+++ b/lib/spack/spack/compilers/xl_r.py
@@ -113,6 +113,12 @@ def fc_version(cls, fc):
            older version of AIX and linux on power.
         """
         fver = get_compiler_version(fc, '-qversion', r'([0-9]?[0-9]\.[0-9])')
+        if fver >= 16:
+            """Starting with version 16.1, the XL C and Fortran compilers
+               have the same version.  So no need to downgrade the Fortran
+               compiler version to match that of the C compiler version.
+            """
+            return str(fver)
         cver = float(fver) - 2
         if cver < 10:
             cver = cver - 0.1