KaloBios Pharmaceuticals Inc. had been left for dead. Now it's the talk of Wall Street.

Shares of the tiny pharmaceutical company are up more than 4000% over the past six trading days, thanks to a high-profile former hedge-fund manager who teamed up with a group of investors to take a majority stake in the firm. The stock traded at 90 cents on Nov. 13, and was above $40 in recent trading Monday.

Shares started their climb Nov. 16, when the stock dropped to as low as 44 cents a share before rocketing to $1.72 on volume of 3.53 million shares. For KaloBios, that counts as extremely heavy volume; it was more than the number of shares that had traded in the prior 36 trading sessions combined.

Then they jumped to $2.17 the next day on even heavier volume of 5.36 million shares.

It was a strange move for the stock, since the firm had announced on Nov. 13 that it was winding down its operations. The South San Francisco-based company said that it had been exploring "strategic transactions," but those efforts had come to naught. Since it had "limited cash resources" remaining, it said it had brought in a restructuring firm and would "phase out" all of its remaining employees over the next month or two.