Icahn recently sold 12.7 million shares of Yahoo, new regulatory filings show, at less than $15. He acquired his stake at an average price of $25 a share last year in an effort to pressure Yahoo into accepting a takeover bid from Microsoft.
That means he's taken a loss of about $130 million. And unless Yahoo's fortunes take an abrupt turn for the better, he's likely to face more losses to come: He still owns a 4.5 percent stake in the company.
After Icahn threatened to vote out Yahoo's board of directors, the company reached an agreement to put Icahn on its board. That's one expensive board seat.
Icahn has admitted that he finds it "hard to understand these technology companies," a fact that Yahoo loudly trumpeted while it fought off Icahn's bid.
Perhaps he should stick to biotech. Whether he understands it or not, it's a part of his portfolio that has seen much better returns than his Yahoo investment.