BP executives sought to reassure jittery investors with a conference call, but said in a statement they had postponed a decision on whether to suspend paying the next quarterly dividend - as some US politicians had demanded.
BP shares had been up 4% but the gains were pared in Friday's session after chief executive Tony Hayward issued the statement.
The US Coast Guard said the containment cap placed on the gushing well about 1.6km beneath the sea was now collecting about 1000 barrels a day.
The collection rate is a small portion of the 19000 barrels a day that the US government has estimated could be gushing from the well.
The captured amount should increase as BP closes vents to trap more oil, said Admiral Thad Allen of the US Coast Guard.
"Some time later today we'll probably be able to get ... an approximation of how much oil we are capturing," Allen said.
Earlier on Friday, BP's chief operating officer Doug Suttles said the containment cap "should work" by capturing at least 90% of the gushing oil.
BP is under pressure to suspend dividend payments, which amount to $10.5-billion a year, and divert the cash to dealing with the spill and clean-up.
The BP statement said: "Future decisions on the quarterly dividend will be made by the board, as they always have been, on the basis of the circumstances at the time.
"All factors will be considered and the decision taken in the long-term interests of the shareholders."
Confronting one of the biggest tests of his presidency as his party prepares for tough congressional elections in November, Obama has called off a trip to Australia and Indonesia to focus on the oil spill.
He is facing criticism as to whether he is doing enough, or showing enough emotion, in dealing with the crisis.
Just R20 for the first month. Support independent journalism by subscribing to our digital news package.