* Says investors worried about potential liability

* Cuts the stocks by a notch to “market perform”

April 30 (Reuters) - FBR Capital Markets cut oilfield services companies Halliburton Energy Services Inc HAL.N and Transocean Ltd RIGN.SRIG.N to "market perform" from "outperform," citing investor worry on potential liability related to the recent oil rig accident in the Gulf of Mexico.

An oil drilling rig, operated by Switzerland-based Transocean and on lease to London-based BP Plc BP.LBP.N, exploded in flames on April 20 and collapsed two days later, leading to massive oil spills. [ID:nSPILL]

Following the incident, a class-action lawsuit was filed against oil giant BP, Transocean, owner of the Deepwater Horizon drilling platform, and Halliburton, which according to the suit, was engaging in cementing operations of the well and well cap. [ID:nN29178997]

“The stocks will be under an overhang of investor worry about their potential liability for this tragic accident for at least several months,” analyst Robert MacKenzie wrote in a note to clients.

MacKenzie also cut his price target on the stock of Transocean to $87 from $110 and on Halliburton’s stock to $35 from $44.

The U.S. Coast Guard estimates that 5,000 barrels of crude oil a day is gushing from the sea floor where the blowout occurred, and authorities have said it could take weeks to cap the leak. [ID:nN29137510]

Shares of Halliburton closed at $31.60, while those of Transocean closed at $78.51 Thursday on the New York Stock Exchange. (Reporting by Krishna N. Das in Bangalore; Editing by Maju Samuel)