Stocks close mostly lower as traders await Friday's Janet Yellen speech

U.S. stocks ticked lower Monday at the start of a trading week that could be defined by Federal Reserve Chair Janet Yellen's much-anticipated speech Friday on the economy and interest-rate policy.

As Yellen's speech approaches, investors are focusing on their never-ending past-time: scrutinizing every incremental development and statement by Fed leaders that could offer clues on the trajectory of interest rates.

In the days leading up to her speech, U.S. markets have been relatively stable. The U.S. economy is close to the U.S. central bank's job and inflation targets, and growth is expected to pick up in the coming months, Stanley Fischer, the central bank's vice chairman, said Sunday.

On Monday, the Dow Jones industrial average fell  23 points, or 0.1% to 18,529.42 The Standard & Poor's 500 index slipped 1.23, or 0.1%, to 2182.64, and the Nasdaq composite index rose 6.22, or 0.1%, at 5244.60.

Oil's decline Monday after a week of solid gains erased some hopes of a newly drama-free recovery for the commodity.

West Texas Intermediate oil, the U.S. benchmark crude, fell about 3% to $46.81 a barrel. Brent crude, the global benchmark, declined 3.4% to $49.17 a barrel.

Investors are watching to see whether the Organization of the Petroleum Exporting Countries reaches a deal on a production freeze at an informal meeting in September.

In the short term, traders will be watching closely to see whether global production picks up as energy companies seek to start pumping again. Any sign of production increases can dampen prices.

The number of active U.S. oil rigs increased by 10 last week, according to Goldman Sachs, which said the total figure is now up 28% since its low point in May.

Follow Paste BN reporter Nathan Bomey on Twitter @NathanBomey.