PTC Therapeutics rallies after unveiling $500 mln stock buyback
** PTC Therapeutics' PTCT.O shares rally 8.7% to more than 1-month high of $66.20 early Tues as it looks to buy back its stock
** PTCT on course for biggest one-day pct gain since 14.3% advance on May 8
** Warren, New Jersey-based firm early Tues announced $500 mln share repurchase program
** Co focuses on developing treatments for rare disorders including Duchenne muscular dystrophy, Friedreich's ataxia and Huntington's disease
** It has ~83.5 mln shares outstanding for ~$5.1 bln market cap as of Mon
** With the advance, shares down ~13% YTD vs Nasdaq Biotech index's .NBI ~28.5% rise
** 13 of 15 analysts rate the stock "strong buy" or "buy", 2 "hold"; median PT $98, according to LSEG data