SAN FRANCISCO -- Maxim Integrated's ( MXIM) exile in backdating purgatory just got a little longer. On Thursday, the Sunnyvale, Calif., chipmaker said it was expanding the number of years for which it would restate past financial results to account for stock-option backdating, and pushed back until spring its expected completion date for the project. Shares of Maxim fell 10.2%, or $2.43, to $21.20 in midday trading. Maxim said it would restate financial results from 1997 through mid-2006, compared with its previous plans to restate results from 2000 through mid 2006. The extra years will add an additional noncash compensation expense of $550 million to $650 million on a pretax basis, or $360 million to $425 million after taxes. What's more, Maxim said it has expanded the scope of the investigation and is now reviewing option grants from 1995 and 1996, as it examines stock options for new groups of employees. As a result, Maxim said its goal of wrapping up its restatement project in the current quarter was no longer feasible, and estimated that the restatements won't be completed until June. That's a blow for investors who have been waiting for Maxim to resume its share repurchases, which have been frozen during the company restatement process. Maxim, which makes analog and mixed-signal chips for everything from cell phones to automobiles, has been embroiled in a particularly long and painful backdating ordeal. The company was delisted from the Nasdaq in October and now trades on the Pink Sheets. In January 2007, Maxim announced the resignation of then-CFO Carl Jasper and of former CEO John Gifford in his role as a strategic adviser to the company.