NEW YORK (AP) -- Hewlett-Packard Co. said Tuesday that a British company it bought for $10 billion last year lied about its finances, resulting in a massive write-down of the value of the business.

HP is avoiding calling it a fraud, but it said there were ``serious accounting improprieties, disclosure failures and outright misrepresentations at Autonomy Corporation PLC.''

HP is taking an $8.8 billion charge in its latest quarter to align the accounting value of Autonomy with its real value. It said most of that charge was due to the fictional bookkeeping at Autonomy.

The revelation is another blow for HP, which is struggling to reinvent itself as PC sales shrink.

Among other things, Autonomy makes search engines that help companies find vital information stored across computer networks. Acquiring it was part of an attempt by HP to strengthen its portfolio of high-value products and services for corporations and government agencies.

HP shares sank almost 11 percent, or $1.45, to $11.85 per share in premarket trading.

HP's net loss for the fiscal fourth quarter, which ended Oct. 31, amounted to $6.85 billion, or $3.49 per share. That compares with net income of $239 million, or 12 cents per share, in the same period last year.

It was the second mammoth loss in a row for HP. In the third fiscal quarter, it lost a record $8.86 billion, or $4.49 per share. That was due to a charge for another acquisition _ that of Electronic Data Systems, a technology consulting service that it bought for $13 billion in 2009. In that case, HP didn't blame improper accounting, just results that didn't live up to expectations.

Excluding the charges in the latest quarter, HP earned $1.16 per share in the latest quarter, just above the average analyst forecast of $1.14 per share, as polled by FactSet.

HP's revenue was $30.0 billion, down 7 percent from last year. That was below analyst expectations at $30.5 billion.