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 Tremor Video Inc. (NYSE:TRMR) initially popped more than 10% Monday morning following Friday's harrowing 49% post-earnings plunge, then fell back into negative territory as the day's trading wore on.

So what: Last week's disappointing quarterly results and weak forward guidance were bad enough to spur no less than three analyst downgrades, but I already stated at the time I wasn't convinced Tremor Video's punishment fit the crime. Given Friday's massive drop, then, this morning's subsequent bounce should come as no surprise.

Now what: Even so, that shares couldn't maintain the rebound shows investors are obviously still skittish with regard to Tremor Video's long-term prospects. To be sure, it's difficult to blame anyone for wanting to stay on the sidelines until Tremor can prove its current weakness is only temporary.