The Securities and Exchange Commission (SEC) said Thursday evening it had begun investigating the causes of a sudden drop yesterday in the stock market.

The SEC and Commodities Future Trading Commission (CFTC) said it was reviewing trading activities that led to a plunge of almost 1,000 points between 2:30 and 3:00 p.m. on Thursday, a momentary panic which roiled markets.

“The SEC and CFTC are working closely with the other financial regulators, as well as the exchanges, to review the unusual trading activity that took place briefly this afternoon," the agencies said in a joint statement. "We are also working with the exchanges to take appropriate steps to protect investors pursuant to market rules."

While markets recovered most of the losses, investors scrambled to figure out the causes of the momentary crash. While the spread of the effects of the Greek debt crisis was thought to contribute in part, reports have indicated that a "fat-fingered trade," where a trader accidentally sold a billion shares instead of a million, might have been to blame.

Already, some lawmakers are calling for a review of how technology glitches can impact high-volume trading as part of the ongoing financial reform effort in Washington.

The SEC and CFTC vowed to make their findings public once they're completed.

"We will make public the findings of our review along with recommendations for appropriate action," the bodies said.