Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of VIVUS (NASDAQ:VVUS), a biopharmaceutical company developing therapies to combat obesity, sleep apnea, diabetes, and sexual dysfunction, spiked higher by as much as 16% following a 13-D filing with the Securities and Exchange Commission from little known Aspen Investment which announced it may make a bid to purchase VIVUS.

So what: According to the 13-D filing, Aspen Investment disclosed a 9.65% stake in VIVUS and announced that it may make a bid to take VIVUS private for a price of $640 million, or what amounts to about $6.19 per share, a 33% premium to yesterday's closing price. As Aspen Investment's 13-D goes on to note, it's under no obligation to actually offer a bid for VIVUS, but assuming it can secure working capital and debt from investment institutions it expects to submit its offer to purchase VIVUS by June 13. Based on commentary from Bloomberg, VIVUS has no comment on the possibility of an offer.

Now what: While this upside is a welcome surprise for investors who've been slammed over the past year on weaker-than-expected sales of weight control management drug Qsymia, I am completely lost as to why Aspen would pay as much as a 33% premium for a company whose losses really aren't shrinking. Qsymia has thus far been a complete dud as an anti-obesity drug, and the possible approval of Orexigen Therapeutics' (NASDAQ: OREX) Contrave which has completed an extensive cardiovascular outcomes study (known as the Light Study) might make it the preferential anti-obesity drug choice among physicians. With few guarantees that Aspen will even follow through with its bid, or even get the funding for that matter, I would consider using today's pop to head for the exit if I were a shareholder.