Synopsys (SNPS) Stock After Hours on Dec. 18, 2025: What Moved Shares After the Bell and What to Watch Before Friday’s Market Open
Synopsys, Inc. (NASDAQ: SNPS) ended Thursday, December 18, 2025, modestly higher in regular trading—then held nearly flat in after-hours as investors digested a fresh round of securities class action headlines and positioned for a potentially more volatile Friday session. In the regular session, SNPS closed at $458.13, up 1.12%, but still lagged several large “semi-adjacent” peers on a day when the broader market advanced. MarketWatch+1By late evening in the extended session, Synopsys was trading around $458 (slightly below the close). StockAnalysis+1 Below is what happened after the bell on Dec. 18—and the key catalysts traders will be watching before the