Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (DJINDICES:^DJI) is unchanged on a slow day for the market. U.S. oil prices dropped, as oil supplies in the U.S. continued their rise for the 10th straight week. As of 1:30 p.m. EST, the Dow was up 20 points, to 16,066. The S&P 500 (SNPINDEX:^GSPC) was up three points, to 1,805.

The  two biggest oil companies in the U.S., ExxonMobil (NYSE:XOM) and Chevron (NYSE:CVX), are both down roughly 0.7% as U.S. oil prices continue to fall. Today, the Energy Information Administration reported U.S. oil supplies rose by 3 million barrels, to 391.4 million barrels.

Crude Oil Stocks

Source: EIA

WTI oil prices are near a six-month low on the news, falling 1.9%, to $91.93 per barrel on the news. While U.S. prices have been dropping, world prices have remained high. The spread between the U.S. oil price, WTI crude, and the international oil price, Brent crude, is now at an eight-month high.

WTI Crude Oil Spot Price Chart

WTI Crude Oil Spot Price data by YCharts

OPEC meets next week -- December 4, to be exact -- to discuss their supply target for 2014. Their current supply target of 30 million barrels per day has been unchanged since 2011. World oil prices remain high as various OPEC members' production is being hampered, and sanctions remain against Iran. The target will likely remain unchanged for the time being.

While U.S. oil prices are dropping, and big oil companies are being punished, Warren Buffett recently bought a $3.4 billion stake in ExxonMobil.

Dan Dzombak can be found on Twitter @DanDzombak or on his Facebook page, DanDzombak. He has no position in any stocks mentioned. The Motley Fool recommends Chevron. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.