Thermo Fisher Scientific Inc. TMO, -0.35% announced Friday a new $2.5 billion stock repurchase program, with no expiration date. The analytical instruments and patient diagnostics company’s new program replaces the current authorization, which had $500 million remaining. Based on Thursday’s stock closing price of $293.54, the new program would allow for the repurchase of up to 8.5 million shares, or about 2.1% of the shares outstanding. The stock rose 0.3% in premarket trading. It has run up 31.2% year to date through Thursday, while the SPDR Health Care Select Sector ETF XLV, +0.22% has gained 9.2% and the S&P 500 SPX, +0.27% has rallied 23.1%.