Updated from 5:24 PM

After-hours trading started off relatively light as just under 750,000 shares changed hands among Instinet's top 20 market movers within 15 minutes of the regular close. Collectively, they gained 0.03%. Then just 15 minutes later, the list had slipped slightly to the negative side, off 0.04% on 824,492 shares. Share volume later picked up, but produced little changes on the list.

Later, Serena Software ( SRNA) was getting pummeled, losing 28%, to $13.75, following a second-quarter earnings and revenue warning and announcing it would cut 12% of its workforce. The company said it would miss the consensus estimate of 23 cents a share and earn between 13 cents and 14 cents in the period. Shares of CDW Computer Centers also were getting hit hard as the company slightly brought down its earnings and revenue predictions for the current quarter.

The most active list was a hodgepodge of the typical after-hours names and some stocks that infrequently lead the extended session. Software game company Take-Two Interactive Software ( TTWO - Get Report) was the top mover in volume, but shares remained unchanged at $18.06, after gaining 25 cents during the regular session.

Nuance Communications ( NUAN), and alternative energy company Plug Power ( PLUG) both were slightly on the plus side, while holding company American International Group ( AIG) was unchanged.

The regulars also made their appearances in the later session. Cisco ( CSCO - Get Report), No. 3 on the Instinet chart, was off 0.7%, to $19.41. Intel ( INTC), which lost 4.4% during the regular session, gained 0.1%, to $30.30 in recent after-hours activity.

On Monday, two Wall Street analysts voiced concerns about price wars among the chipmakers, and struggles in the computer sector, which spells trouble for Intel. Dell ( DELL) and Microsoft ( MSFT ) were both off slightly on light volume.

10 most active stocks on Island ECN (5:00 p.m. EDT)
Company Price Change Session Volume
Nasdaq 100 Tracking Stock (QQQ) 42.48 N/A 51,702
Exodus Communications 1.79 +0.02 48,248
Metromedia Fiber Network /FONT> 0.91 +0.01 41,468
JDS Uniphase (JDSU) 9.50 +0.05 34,401
Cisco Systems (CSCO - Get Report) 19.43 -0.11 28,947
Telenetics Corporation (TLNT) 0.60 +0.05 21,188
Openwave Systems 24.65 +0.06 15,965
Oracle (ORCL) 17.48 +0.02 15,285
i2 Technologies 10.10 +0.04 13,760
Razorfish (RAZF) 0.45 +0.02 12,800

Island ECN offers trading, mainly in Nasdaq-listed stocks, from 7 a.m. to 8 p.m. EST.

Confused? TheStreet.com explains how the rules change when the sun goes down in Investing Basics: Night Owl, a section devoted to after-hours trading.