diff --git a/src/spicelib/devices/bsim4/b4.c b/src/spicelib/devices/bsim4/b4.c
index 1842af5f4..a37a78c84 100644
--- a/src/spicelib/devices/bsim4/b4.c
+++ b/src/spicelib/devices/bsim4/b4.c
@@ -54,6 +54,7 @@ IOP( "rbpb", BSIM4_RBPB,  IF_REAL   , "Body resistance"),
 IOP( "rbps", BSIM4_RBPS,  IF_REAL   , "Body resistance"),
 IOP( "rbpd", BSIM4_RBPD,  IF_REAL   , "Body resistance"),
 IOP( "delvto", BSIM4_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
+IOPR( "delvt0", BSIM4_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
 IOP( "xgw",  BSIM4_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4_NGCON, IF_REAL, "Number of gate contacts"),
 
diff --git a/src/spicelib/devices/bsim4v5/b4v5.c b/src/spicelib/devices/bsim4v5/b4v5.c
index 983f8fe2b..2ce31148b 100644
--- a/src/spicelib/devices/bsim4v5/b4v5.c
+++ b/src/spicelib/devices/bsim4v5/b4v5.c
@@ -45,6 +45,7 @@ IOP( "rbpb", BSIM4v5_RBPB,  IF_REAL   , "Body resistance"),
 IOP( "rbps", BSIM4v5_RBPS,  IF_REAL   , "Body resistance"),
 IOP( "rbpd", BSIM4v5_RBPD,  IF_REAL   , "Body resistance"),
 IOP( "delvto", BSIM4v5_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
+IOPR( "delvt0", BSIM4v5_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
 IOP( "xgw",  BSIM4v5_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4v5_NGCON, IF_REAL, "Number of gate contacts"),
 
diff --git a/src/spicelib/devices/bsim4v6/b4v6.c b/src/spicelib/devices/bsim4v6/b4v6.c
index 7c0c8d2b0..1e45b95e2 100644
--- a/src/spicelib/devices/bsim4v6/b4v6.c
+++ b/src/spicelib/devices/bsim4v6/b4v6.c
@@ -51,6 +51,7 @@ IOP( "rbpb", BSIM4v6_RBPB,  IF_REAL   , "Body resistance"),
 IOP( "rbps", BSIM4v6_RBPS,  IF_REAL   , "Body resistance"),
 IOP( "rbpd", BSIM4v6_RBPD,  IF_REAL   , "Body resistance"),
 IOP( "delvto", BSIM4v6_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
+IOPR( "delvt0", BSIM4v6_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
 IOP( "xgw",  BSIM4v6_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4v6_NGCON, IF_REAL, "Number of gate contacts"),
 
diff --git a/src/spicelib/devices/bsim4v7/b4v7.c b/src/spicelib/devices/bsim4v7/b4v7.c
index e12221855..ea633ee38 100644
--- a/src/spicelib/devices/bsim4v7/b4v7.c
+++ b/src/spicelib/devices/bsim4v7/b4v7.c
@@ -52,6 +52,7 @@ IOP( "rbpb", BSIM4v7_RBPB,  IF_REAL   , "Body resistance"),
 IOP( "rbps", BSIM4v7_RBPS,  IF_REAL   , "Body resistance"),
 IOP( "rbpd", BSIM4v7_RBPD,  IF_REAL   , "Body resistance"),
 IOP( "delvto", BSIM4v7_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
+IOPR( "delvt0", BSIM4v7_DELVTO,  IF_REAL   , "Zero bias threshold voltage variation"),
 IOP( "xgw",  BSIM4v7_XGW, IF_REAL, "Distance from gate contact center to device edge"),
 IOP( "ngcon", BSIM4v7_NGCON, IF_REAL, "Number of gate contacts"),
 
diff --git a/src/spicelib/devices/bsimsoi/b4soi.c b/src/spicelib/devices/bsimsoi/b4soi.c
index 9a35ec384..319a51cbb 100644
--- a/src/spicelib/devices/bsimsoi/b4soi.c
+++ b/src/spicelib/devices/bsimsoi/b4soi.c
@@ -92,6 +92,7 @@ IOP( "nf",  B4SOI_NF,     IF_REAL   , "Number of fingers"),
 IOP( "rbdb", B4SOI_RBDB,  IF_REAL   , "Body resistance"),
 IOP( "rbsb", B4SOI_RBSB,  IF_REAL   , "Body resistance"),
 IOP( "delvto", B4SOI_DELVTO,  IF_REAL, "Zero bias threshold voltage variation"),
+IOPR( "delvt0", B4SOI_DELVTO,  IF_REAL, "Zero bias threshold voltage variation"),
 /* v4.0 end */
 
 IOP( "soimod", B4SOI_SOIMOD, IF_INTEGER,    "Instance model selector for PD/FD operation"), /* v3.2 */