Shares of Valencia biopharmaceutical company MannKind Corp. continued to rise Thursday on speculation that the company may be headed for acquisition.

Shares climbed 62 cents, or almost 10 percent, to close at $6.85 on the Nasdaq. And on Wednesday, shares jumped almost 16 percent after an article was published speculating that the company was a prime acquisition target.

Company officials said they have no announcements in the works that would cause an increase in share price.

The company is conducting additional clinical trials of its primary pipeline product, inhaled insulin drug Afrezza. The Food and Drug Administration called for more research on the drug in 2011, and the company plans to resubmit Afrezza for FDA approval later this year.

The company went public in 2004 and has yet to report a profit. Most income has come through secondary offerings and the backing of its founder, billionaire entrepreneur Alfred Mann.

In December, Mann converted more than $107 million debt owed to him by MannKind into 40 million shares and warrants to purchase another 30 million.