The

Securities and Exchange Commission

is taking a look at

Doral's

(DRL)

books.

The Puerto Rico-based bank said Wednesday that the agency was conducting an informal investigation related to the company's planned restatement. Doral said Tuesday it

might restate earnings by as much as $600 million because of continuing problems with its use of interest rate-only strips, a special type of security, to hedge its mortgage portfolio.

The restatement news came after Doral had seen its shares lose nearly two-thirds of their value amid worries about the company's use of so-called derivatives.

Doral said it would cooperate with the SEC.

Early Wednesday, Doral sank $1 to $15.15.