PTGX ▲ +0.2% - Protagonist Therapeutics, Inc. $PTGX - Protagonist Therapeutics Announces $300 Million Share Repurchase Program Protagonist Therapeutics announced a $300 million share repurchase program, which signals management confidence in the company's valuation and can reduce share count to benefit per-share metrics. The stock edged up 0.2% on the news, a modest reaction that reflects investor acknowledgment of the buyback authorization. 08-SEP-2026 04:05 PM ET