The Dow Jones Industrial average lost 620.74 points, or 2%, to 29,982.62, the first time the 30-stock gauge has closed below the 30,000 mark since Dec. 14. The S&P 500 fell 1.9% to 3,714.24 as 10 sectors registered losses. The Nasdaq Composite slid 2% to 13,070.69 as Apple dropped 3.7% and other major tech names slipped.

All three major averages dropped more than 3% this week, posting their worst week since October. For January, the blue-chip Dow and the S&P 500 fell 2% and 1.1%, respectively, suffering their first negative month in four. The tech-heavy Nasdaq eked out a 1.4% gain on the month.

Shares of GameStop jumped 67.9% after Robinhood said it would allow limited buying of the stock and other heavily shorted names after restricting access the day before. Robinhood raised more than $1 billion from its existing investors overnight, in addition to tapping bank credit lines, to ensure it had the capital required to allow some trading again in volatile stocks like GameStop.

Investors are concerned that if GameStop continues to rise in such a volatile fashion, it may ripple through the financial markets, causing losses at brokers like Robinhood and forcing hedge funds who bet against the stock to sell other securities to raise cash.

There are also fears that the GameStop mania is a sign of a larger bubble in the market and that its unraveling could also cause turbulence and hit retail investors hard. A number of lawmakers also called for an investigation into the chaotic trading. The Securities and Exchange Commission said Friday it will look into regulated body's actions to uncover if the decisions made disadvantaged investors.