Bristol-Myers Squibb just can’t seem to catch a break. The drugmaker’s fourth-quarter revenue grew by 33 per cent year-on-year, after sales of anti-clotting drug Plavix skyrocketed when a generic competitor was forced out of the market. But this good news was marred by a $275m write-off of the company’s holdings of securities that are backed, in part, by subprime mortgages.

Nearly every US company has suffered from indirect exposure to the housing crisis. Until recently, however, writedowns of direct investments in land or mortgage-backed securities have been confined to the financial and homebuilding sectors. But Bristol-Myers now says the market value of a pool of securities it owns has dropped from $811m to $419m, even though they were rated triple-A when purchased.