Merck (MRK) Stock After Hours: FDA Fast‑Track Vouchers, Keytruda‑Padcev Trial Win, and What to Watch Before the Dec. 18 Market Open
Merck & Co., Inc. (NYSE: MRK) finished regular trading on Wednesday, Dec. 17, 2025 in positive territory, then held near the $99 level in extended hours as investors weighed two major pipeline headlines—one before the opening bell and another after