Thursday's Late Winners & Losers

Stocks were mostly slipping in after-hours action Thursday as a number of names weighed things down with soft guidance and poor financials.

Software company Parametric Technology (PMTC Quote), was among the worst losers, tumbling 22.4% to $16.75 after ratcheting down its fiscal third-quarter sales outlook to about $225 million, vs. the prior range of between $235 million and $240 million. The Needham, Mass., company didn't specify earnings guidance, but income should now come in below the prior forecast of 26 cents to 29 cents a share (on a non-GAAP basis). Analysts polled by Thomson Financial are seeking 28 cents a share on $238.2 million in revenue.

Interactive Brokers Group (IBKR Quote), of Greenwich, Conn., slid 10.4% after pegging second-quarter adjusted earnings at 32 cents to 34 cents a share on adjusted sales of $316 million to $335 million. The expected profit squares with two analysts' projections, but revenue should miss the sole target by at least $17 million. Shares were down $2.81 at $24.30.

Also falling on poor guidance was Healthways (HWAY Quote), which reported in-line earnings for the fiscal third quarter but lowered its full-year forecast by at least 22 cents, now expecting between $1.21 and $1.22 a share. The Nashville, Tenn., purveyor of health- and care-support programs shed $1.79, or 3.6%, to $47.85.

Similarly, California-based semiconductor Applied Micro Circuits (AMCC Quote) cut its revenue guidance by $9.6 million to about $50 million for the quarter ended June 30 -- $10 million under the consensus. Shares dropped immediately after the closing bell in substantial trading; recently, they lifted by 0.8% to $2.46 in thin volume.

Also on the upswing was amusement-park operator Six Flags (SIX Quote). The New York-based outfit gained 3.4% after hedge fund SAC Capital Management reported that it had purchased a 5.2% stake in the company, or about 5 million shares. Shares were recently trading at $6.09.