Oil companies shares down at 10 a.m.

Shares of some top oil companies are down at 10 a.m.:

BP PLC fell $.32 or .6 percent, to $52.30.

Chevron fell $1.46 or 1.1 percent, to $129.77.

ConocoPhillips fell $.82 or 1.0 percent, to $84.80.

Exxon Mobil Corp. fell $1.01 or 1.0 percent, to $101.13.

Marathon Oil Corp. fell $.24 or .6 percent, to $39.47.