(Bloomberg) ? Global Crossing Ltd., a fibre-optic network operator that left bankruptcy in December, said it will restate first-quarter results, boosting expenses by $66 million to reflect costs incurred in 2003.

Expenses for the use of other carriers? networks were underreported by $66 million, Hamilton, Bermuda-based Global Crossing in a statement. Deloitte & Touche LLP reviewed the restatement and didn?t find ?any management integrity issues,? Global Crossing said.

The company?s internal review, announced in April, came as a surprise to investors who thought the company?s books were scrubbed clean during its two-year bankruptcy. Global Crossing, already under a US Securities and Exchange Commission investigation of other matters, said in April it may have understated the liability by $50 million to $80 million.

Shares of Global Crossing, which is run from Florham Park, New Jersey, rose $2.10, or 13 percent, to $18.80 in Nasdaq Stock Market composite trading. Results of the financial-statement review were disclosed after regular trading ended. Mexican billionaire Carlos Slim disclosed yesterday that he had boosted his Global Crossing stake to 10.7 percent. Separately, Global Crossing asked the Nasdaq Stock Market for a further extension until September 10 to comply with listing requirements. Audited financial statements are required for a Nasdaq listing, and the company said in April its financial statements were no longer reliable. The shares will continue to trade there while the extension request is considered, Global Crossing said.