ATII ▼ -0.1% - Archimedes Tech SPAC Partners II Co. $ATII ATIIU - Archimedes Tech SPAC Partners II Co. Announces Filing of Third Amendment to Registration Statement on Form S-4 with the SEC Archimedes Tech SPAC Partners II Co. announced the filing of a third amendment to its Form S-4 registration statement with the SEC. The stock declined 0.1% on the news, a minimal move that suggests investors viewed the procedural filing as routine. 02-SEP-2026 05:01 PM ET