The “highly sophisticated and damaging cyberattack” crippled Sony Pictures Entertainment’s accounting applications until February, leaving it unable to meet a February 16 deadline to file its complete quarterly financial report, the company says in a filing today to the Financial Services Agency of Japan and the SEC. It asked for an extension to the end of March. Although it believes the financial impact of the attack “is not material,” Sony says it’s still calculating.

It has a big job ahead. The attack resulted in “a serious disruption of SPE’s network systems…including the destruction of network hardware and the compromise of a large amount of data on these systems,” the filing says. “In response to this cyberattack, SPE shut down its entire network.”

Next month, when the systems are running again, SPE will begin to enter and verify data for the two months when it was off line. Sony says it “cannot complete its preparation, including the review by our independent accountants” on time.

Even so, Sony will issue an incomplete release on February 4 and will provide analysts and press with “updated forecasts of Sony’s consolidated financial results” for the quarter “to the extent reasonably possible, based on the information available on that date.”

Sony shares were up 4.8% today in Tokyo trading.