Rowan plans to move headquarters to U.K.

Rowan Companies Inc., the offshore- drilling contractor that shed $1.6 billion of its business units last year, fell the most in more than three months after announcing plans to move its legal headquarters to the United Kingdom.

Rowan, which owns 31 shallow-water rigs and is building 3 ultra-deepwater drillships, fell 6.5 percent to $36.02 at 1:18 p.m. in New York. Earlier, the shares fell as much as 7 percent, the biggest intraday drop since Nov. 1.

The company, a member of the Standard & Poor’s 500 Index that is based in Houston and legally domiciled in Delaware, plans to exchange U.S. stock for American depositary shares and rename itself Rowan Companies Plc, the company said today in a statement. The plan is subject to shareholder approval.

“People are going to get out of it early before the S&P 500 removal gets announced,” Brian Uhlmer, an analyst at Global Hunter Securities LLC in Houston, said in a telephone interview. “There’s going to be a little bit of noise in the name as it gets put into a new European index.”

Rowan reported fourth-quarter adjusted earnings per share that was 2 cents higher than the average of 30 analysts’ estimates compiled by Bloomberg, according to a statement.

The company is moving to be closer to customers in the U.K., Europe and Egypt, according to a statement. Rowan estimates 81 percent of sales this year will come from outside the U.S., up from 10 percent in 2004.

No senior management will relocate to the U.K., Chief Executive Officer Matt Ralls said in a conference call with investors today.