NEW YORK (TheStreet) -- The S&P 500 closed its sixth week of straight gains, although its down for the day during this shortened holiday session. Plummeting oil prices proved a boon to retail and airline stocks, balancing out the selloff among energy stocks on the S&P 500.
OPEC agreed not to cut oil production to address oversupply, but instead said at its Thursday meeting it would maintain current levels of 30 million barrels a day. In a statement, OPEC members said it would take such action "in the interest of restoring market equilibrium."
The crude oil benchmark West Texas Intermediate plummeted 7.7% to $68 a barrel. Oil prices have dropped 35% since mid-year.
Airline stocks were gaining as investors predicted the slip in gas prices might benefit the carriers' profitability. Southwest Airlines (LUV) added 6.5%, Delta Air Lines (DAL) climbed 5.5%, and United Continental (UAL) gained 8.2%.