By Polya Lesova, MarketWatch
NEW YORK (MarketWatch) -- Oil futures swung between gains and losses Friday, as U.S. stock-index futures fell and the U.S. dollar weakened against major rivals.
Trading was very volatile. Light sweet crude for September delivery was last down 20 cents to $70.33 a barrel in electronic trading on Globex.
On Wall Street, stock index futures pointed to a lower opening after data showed that U.S. consumer prices were unchanged in July.
Also due this morning is the Federal Reserve's estimate of July industrial production. It's expected to show a 0.7% rise after a 0.4% fall in June.
Earlier in the session, oil prices had gained, as the U.S. dollar fell against the Japanese yen. Dollar weakness typically boosts dollar-denominated commodities. See Currencies.
The dollar index (DXY 78.33, -0.16, -0.21%) , which measures the U.S. unit against a basket of six major currencies, edged down to 78.272 compared with 78.390.
Crude futures ended slightly higher on the New York Mercantile Exchange Thursday, aided by the dollar's weakness and better-than-expected economic data from Germany and France. See full story.
"The discrepancy between the current oil price level and the underlying oil market fundamentals is widening," wrote analysts at Commerzbank.
"This mismatch can only be explained by the strong correlation between the oil price and financial markets' sentiment," they said. "Excluding this particular aspect, the oil price would possibly trade at a much lower level."
Also on Globex, September reformulated gasoline rose 0.3% to $2.0246 a gallon and September heating oil gained 0.4% to $1.9097 a gallon.
September natural-gas futures rose 0.9% to $3.364 per million British thermal units.
