NEW YORK (TheStreet) -- Shares of Transocean  (RIG - Get Report) are falling 3.01% to $11.77 in afternoon trading on Monday after Seaport Global cut its rating on the stock to "sell" from "neutral."

The firm maintained its $10 price target on shares of the Swiss offshore contract drilling company.

"Transocean shares have rallied 34.1% since May 23, and the valuation seems stretched at this point given that little has changed regarding the protracted oversupply of rigs in offshore markets," the firm wrote in a note cited by Barron's.

The company also will have a higher annual cash interest expense burden due to last week's $1.25 billion unsecured note issuance, Seaport Global said.

Further weighing on shares today, oil prices are retreating this afternoon amid continued uncertainty surrounding the fallout from Britain's recent decision to leave the European Union.

Separately, TheStreet Ratings team rates the stock as a "sell" with a ratings score of D+.

Transocean's weaknesses include a generally disappointing historical performance in the stock itself.

You can view the full analysis from the report here: RIG

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.