Shares of

Network Associates

(NET) - Get Report

sank Thursday after the security software maker lowered revenue guidance for the full year while also announcing it met estimates for the second quarter.

Shares of Network Associates tumbled $3.25, or 18.4%, to $14.45 in recent trading.

Before the market opened, Network Associates reported GAAP net income of $21.2 million, or 12 cents a share, in the second quarter, compared with a net loss of $37.2 million, or 27 cents a share, basis, in the same period a year earlier.

Santa Clara, Calif.-based Network Associates said excluding

McAfee.com

(MCAF)

, of which it owns 75% and is seeking to acquire the remaining 25%, it earned pro forma net income of $20.5 million, or 12 cents a share, compared with a pro forma net loss of $2.7 million, or 2 cents a share, a year earlier. The company said revenue rose 21% to $233 million from $192.6 million a year earlier and 5.6% from $220.7 million in the previous quarter.

Wall Street analysts were expecting Network Associates to earn 12 cents a share on $224.5 million in the second quarter, according to Thomson Financial/First Call.

Excluding McAfee, Network Associates said it expects third-quarter revenue to range from $205 million to $215 million. And Network Associates expects third-quarter earnings to range from 11 cents to 13 cents a share, excluding McAfee. The consensus estimate among analysts was for 14 cents a share on $231 million in revenue in the third quarter.

For the full year, Network Associates expects revenue excluding McAfee to be at the low end of previously stated guidance, which the company raised in April to between $875 million and $900 million. The company reiterated guidance for pro forma net earnings, excluding McAfee and other charges, ranging from 50 cents to 55 cents a share. Analysts were expecting earnings of 55 cents a share on $1 billion in revenue for the full year.

On July 1, Network Associates announced its third bid to buy 25% of McAfee that it doesn't already own. The company offered to pay 0.78 of a share of Network Associates for every outstanding share of McAfee common stock in a deal valued at $180.4 million based on June 28 closing prices.

That was the same sweetened exchange ratio previously offered by Network Associates and was a slight premium over McAfee's June 28 closing price. But it is lower than the last offer worth $224 million because Network Associates' stock price has fallen.

A special committee of McAfee's board is reviewing the offer. Network Associates abandoned its previous attempt to buy back McAfee, which it spun off during the dot-com boom to sell security software via the Internet, because it was forced to restate financial numbers. Network Associates is still being investigated by the

Securities and Exchange Commission

.