U.S. stocks closed their worst week in months Friday as crude oil prices plunged to a near seven-year low and investors prepared for the first U.S. interest rate hike in nearly a decade. Uplifting news that U.S. retail sales saw their biggest increase since July had little impact on equities as investors shed risk and piled into the relative safety of U.S. Treasury bonds.

“Today has been all about the drop in crude oil and of course the expectation that the Fed is going to raise the rate next week,” said Peter Cardillo, chief market economist at New York advisers First Standard Financial. “Investors are repositioning their portfolios ahead of the rate hike. Obviously, we’re headed for an ugly week.”

The Dow Jones Industrial Average (INDEXDJX:.DJI) closed Friday down 309.54 points, or 1.76 percent, at 17,265. The broader Standard & Poor's 500 stock index (INDEXSP:.INX) fell 39.86 points, or 1.94 percent, to 2,012. The Nasdaq composite (INDEXNASDAQ:.IXIC) lost 111.71 points, or 2.21 percent, to 4,933.

All 10 S&P 500 sectors were down by as much as 3.38 percent, led by energy and materials companies. All 30 Dow components fell Friday, led by chemicals giant E.I. Du Pont De Nemours & Co. (NYSE:DD), commonly known as DuPont, which shed 5.51 percent to $70.44 after a proposed merger with Dow Chemical Co. (NYSE:DOW) was announced Friday morning.

The S&P 500 posted its biggest weekly percentage drop in more than 3 1/2 months while the other two major U.S. indexes posted their biggest weekly declines in a month, Reuters said.

Crude oil prices continued their relentless plunge Friday as futures traders continued to review the implications of OPEC’s announcement last week that it would continue to send barrels to the market despite a global glut in a punishing bid to maintain its market share. A strong U.S. dollar and unseasonably warm U.S. weather hasn’t helped.

West Texas Intermediate crude oil, the U.S. benchmark for oil prices, dropped 3.48 percent to $35.48 per barrel for January delivery on the New York Mercantile Exchange. Brent crude, the global benchmark oil price, plunged 4.63 percent to $37.89 for January delivery on the London ICE Futures Exchange. Brent prices closed at less than $40 a barrel Thursday for the first time since the 2007-09 Great Recession.