diff --git a/test_regress/t/t_covergroup_auto_bins.v b/test_regress/t/t_covergroup_auto_bins.v
index 9b8726006..2459997df 100644
--- a/test_regress/t/t_covergroup_auto_bins.v
+++ b/test_regress/t/t_covergroup_auto_bins.v
@@ -4,6 +4,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t;
diff --git a/test_regress/t/t_covergroup_auto_sample.cpp b/test_regress/t/t_covergroup_auto_sample.cpp
index 7dca61543..771eaa90c 100644
--- a/test_regress/t/t_covergroup_auto_sample.cpp
+++ b/test_regress/t/t_covergroup_auto_sample.cpp
@@ -3,6 +3,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 #include "verilated.h"
diff --git a/test_regress/t/t_covergroup_auto_sample.v b/test_regress/t/t_covergroup_auto_sample.v
index 25739de7d..7e8780ebc 100644
--- a/test_regress/t/t_covergroup_auto_sample.v
+++ b/test_regress/t/t_covergroup_auto_sample.v
@@ -1,6 +1,7 @@
 // DESCRIPTION: Verilator: Test automatic sampling with clocking events
 // Tests --no-timing (default) mode; see t_covergroup_auto_sample_timing for --timing variant.
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t (/*AUTOARG*/
diff --git a/test_regress/t/t_covergroup_autobins.v b/test_regress/t/t_covergroup_autobins.v
index 7d68aa225..ddae6c784 100644
--- a/test_regress/t/t_covergroup_autobins.v
+++ b/test_regress/t/t_covergroup_autobins.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // verilog_format: off
diff --git a/test_regress/t/t_covergroup_clocking_internal.v b/test_regress/t/t_covergroup_clocking_internal.v
index 39a245780..695cf855c 100644
--- a/test_regress/t/t_covergroup_clocking_internal.v
+++ b/test_regress/t/t_covergroup_clocking_internal.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test: Covergroup with INTERNAL clock using explicit sampling
diff --git a/test_regress/t/t_covergroup_clocking_module_input.v b/test_regress/t/t_covergroup_clocking_module_input.v
index c38d5ff94..ab8303141 100644
--- a/test_regress/t/t_covergroup_clocking_module_input.v
+++ b/test_regress/t/t_covergroup_clocking_module_input.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test: Covergroup with clocking event using MODULE INPUT clock
diff --git a/test_regress/t/t_covergroup_coverage_pct.v b/test_regress/t/t_covergroup_coverage_pct.v
index 1e8026b1d..ea4b6c829 100644
--- a/test_regress/t/t_covergroup_coverage_pct.v
+++ b/test_regress/t/t_covergroup_coverage_pct.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // verilog_format: off
diff --git a/test_regress/t/t_covergroup_cross_large.v b/test_regress/t/t_covergroup_cross_large.v
index 1f40d3ce1..3a5ba1cc0 100644
--- a/test_regress/t/t_covergroup_cross_large.v
+++ b/test_regress/t/t_covergroup_cross_large.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // verilog_format: off
diff --git a/test_regress/t/t_covergroup_cross_large_main.cpp b/test_regress/t/t_covergroup_cross_large_main.cpp
index b0d79ea49..bf643fc15 100644
--- a/test_regress/t/t_covergroup_cross_large_main.cpp
+++ b/test_regress/t/t_covergroup_cross_large_main.cpp
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 #include <verilated.h>
diff --git a/test_regress/t/t_covergroup_cross_small.v b/test_regress/t/t_covergroup_cross_small.v
index 415c4e1de..91ecc0d44 100644
--- a/test_regress/t/t_covergroup_cross_small.v
+++ b/test_regress/t/t_covergroup_cross_small.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test small cross coverage with inline implementation
diff --git a/test_regress/t/t_covergroup_dynamic.v b/test_regress/t/t_covergroup_dynamic.v
index d9a7d9b2f..b580e0f78 100644
--- a/test_regress/t/t_covergroup_dynamic.v
+++ b/test_regress/t/t_covergroup_dynamic.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // verilog_format: off
diff --git a/test_regress/t/t_covergroup_empty.cpp b/test_regress/t/t_covergroup_empty.cpp
index 759c358d5..f25482bde 100644
--- a/test_regress/t/t_covergroup_empty.cpp
+++ b/test_regress/t/t_covergroup_empty.cpp
@@ -3,6 +3,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 #include "verilated.h"
diff --git a/test_regress/t/t_covergroup_empty.v b/test_regress/t/t_covergroup_empty.v
index ba9e5d93e..34f37c581 100644
--- a/test_regress/t/t_covergroup_empty.v
+++ b/test_regress/t/t_covergroup_empty.v
@@ -1,5 +1,6 @@
 // DESCRIPTION: Verilator: Verilog Test module - Edge case: empty covergroup
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test: Empty covergroup (no coverpoints)
diff --git a/test_regress/t/t_covergroup_get_coverage.v b/test_regress/t/t_covergroup_get_coverage.v
index d0f0338aa..02b4f620a 100644
--- a/test_regress/t/t_covergroup_get_coverage.v
+++ b/test_regress/t/t_covergroup_get_coverage.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t (input clk);
diff --git a/test_regress/t/t_covergroup_iff.v b/test_regress/t/t_covergroup_iff.v
index fe848ddd6..b605f420b 100644
--- a/test_regress/t/t_covergroup_iff.v
+++ b/test_regress/t/t_covergroup_iff.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t (input clk);
diff --git a/test_regress/t/t_covergroup_illegal_bins.v b/test_regress/t/t_covergroup_illegal_bins.v
index cacfd7558..99bf01420 100644
--- a/test_regress/t/t_covergroup_illegal_bins.v
+++ b/test_regress/t/t_covergroup_illegal_bins.v
@@ -4,6 +4,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2026 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t;
diff --git a/test_regress/t/t_covergroup_multi_instance.v b/test_regress/t/t_covergroup_multi_instance.v
index ab775e765..1dd8a87cd 100644
--- a/test_regress/t/t_covergroup_multi_instance.v
+++ b/test_regress/t/t_covergroup_multi_instance.v
@@ -1,5 +1,6 @@
 // DESCRIPTION: Verilator: Verilog Test module - Edge case: multiple instances
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test: Multiple instances of same covergroup type sampling the same coverpoint
diff --git a/test_regress/t/t_covergroup_negative_ranges.v b/test_regress/t/t_covergroup_negative_ranges.v
index a260a8ff6..78c2d5e94 100644
--- a/test_regress/t/t_covergroup_negative_ranges.v
+++ b/test_regress/t/t_covergroup_negative_ranges.v
@@ -1,5 +1,6 @@
 // DESCRIPTION: Verilator: Verilog Test module - Edge case: negative value ranges
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // Test: Bins with negative value ranges
diff --git a/test_regress/t/t_covergroup_static_coverage.v b/test_regress/t/t_covergroup_static_coverage.v
index 3dcfc3172..e0c33499e 100644
--- a/test_regress/t/t_covergroup_static_coverage.v
+++ b/test_regress/t/t_covergroup_static_coverage.v
@@ -6,6 +6,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-FileCopyrightText: 2024 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 // verilog_format: off
diff --git a/test_regress/t/t_covergroup_trans_3value.v b/test_regress/t/t_covergroup_trans_3value.v
index dc8d4407a..13ed0190e 100644
--- a/test_regress/t/t_covergroup_trans_3value.v
+++ b/test_regress/t/t_covergroup_trans_3value.v
@@ -2,6 +2,7 @@
 // Known limitation: multi-value (3+) transition bins generate incomplete case
 // statements; complex transitions are not fully supported.
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t;
diff --git a/test_regress/t/t_covergroup_trans_ranges.v b/test_regress/t/t_covergroup_trans_ranges.v
index 2321c21fe..ee975b02b 100644
--- a/test_regress/t/t_covergroup_trans_ranges.v
+++ b/test_regress/t/t_covergroup_trans_ranges.v
@@ -1,6 +1,7 @@
 // DESCRIPTION: Verilator: Test transition bins - array bins
 // Transition array bins are supported.
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t (/*AUTOARG*/
diff --git a/test_regress/t/t_covergroup_trans_restart.v b/test_regress/t/t_covergroup_trans_restart.v
index ec7b3357c..5d3e7af24 100644
--- a/test_regress/t/t_covergroup_trans_restart.v
+++ b/test_regress/t/t_covergroup_trans_restart.v
@@ -2,6 +2,7 @@
 // Known limitation: multi-value transition bins with restart semantics generate
 // incomplete case statements; complex transitions are not fully supported.
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t;
diff --git a/test_regress/t/t_covergroup_trans_simple.v b/test_regress/t/t_covergroup_trans_simple.v
index 6ceb42c84..bcd181237 100644
--- a/test_regress/t/t_covergroup_trans_simple.v
+++ b/test_regress/t/t_covergroup_trans_simple.v
@@ -1,5 +1,6 @@
 // DESCRIPTION: Verilator: Test transition bins - simple two-value transitions
 // This file ONLY is placed into the Public Domain, for any use, without warranty.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 module t (/*AUTOARG*/
diff --git a/test_regress/t/t_covergroup_with_sample_args_too_many_bad.py b/test_regress/t/t_covergroup_with_sample_args_too_many_bad.py
index dff5516bf..578412ac0 100755
--- a/test_regress/t/t_covergroup_with_sample_args_too_many_bad.py
+++ b/test_regress/t/t_covergroup_with_sample_args_too_many_bad.py
@@ -1,10 +1,10 @@
 #!/usr/bin/env python3
 # DESCRIPTION: Verilator: Verilog Test driver/expect definition
 #
-# Copyright 2025 by Wilson Snyder. This program is free software; you
-# can redistribute it and/or modify it under the terms of either the GNU
-# Lesser General Public License Version 3 or the Perl Artistic License
-# Version 2.0.
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2025 Wilson Snyder
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
 import vltest_bootstrap
diff --git a/test_regress/t/t_covergroup_with_sample_args_too_many_bad.v b/test_regress/t/t_covergroup_with_sample_args_too_many_bad.v
index 60ba2dc26..a70c0d971 100644
--- a/test_regress/t/t_covergroup_with_sample_args_too_many_bad.v
+++ b/test_regress/t/t_covergroup_with_sample_args_too_many_bad.v
@@ -2,6 +2,7 @@
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
 // any use, without warranty, 2025 by Antmicro.
+// SPDX-FileCopyrightText: 2025 Wilson Snyder
 // SPDX-License-Identifier: CC0-1.0
 
 /* verilator lint_off COVERIGN */