The Standard & Poor's 500 stock index closed Friday at 2416.62, teetering near bear market territory and threatening to end the 10-year bull market, the longest in U.S. history.

The S&P 500 hit an all-time closing high on September 20th, but has swiftly plunged by 17.8% since then, and its near bear market territory.

Friday's loss of 2% on top of Thursday's drubbing of 1.6% came in reaction to the Federal Reserve Board of Governors Chairman, Jerome Powell's, announcement on Thursday afternoon of a quarter-point hike in its key lending rate.