An internal investigation at

KLA-Tencor

(KLAC) - Get Report

has found discrepancies in its past stock-option grant dates, the company announced Friday.

As a result, the company said it now anticipates that it may record additional noncash charges for stock-based compensation expense, although it's still unclear whether the charges will be material and cause KLA to restate previous financial reports.

KLA is among dozens of companies caught up in a widening investigation into the practice of backdating stock options. In May, KLA disclosed that it has received subpoenas from Justice Department lawyers in California and New York regarding its past stock-option practices and that the company had appointed a special committee to look into options granted between 1995 and 2001.

On Friday, KLA said the committee has reached a preliminary conclusion "that the actual measurement dates for financial accounting purposes of certain stock-option grants issued in prior years likely differ from the recorded grant dates of such awards."

The company said the special committee has not yet completed its investigation and is continuing its review of these matters.

Shares of KLA were off 2%, or 83 cents, at $41.16 in midday trading.