Many biotechnology stocks fell on Tuesday as investors struggled to understand the impact of a ruling that threw out parts of two gene patents and called into question thousands more.
Stock market losses were muted, with two major indexes that track the shares of the industry falling by less than 1 percent each. In part, that was because biotechnology executives hastened to reassure their investors that the ruling would not necessarily undermine their businesses, at least in the short run.
But the executives themselves were struggling on Tuesday to figure out what the long-term impact would be. Biotech companies spend billions every year trying to develop new tests and treatments based partly on genes they have isolated and patented.
In a far-reaching ruling, Judge Robert W. Sweet anticipated a negative reaction from the industry. In a footnote of his 152-page ruling, he discounted fears that invalidating such patents would decimate the industry.