Updated from 5:19 p.m. EDT

Genesis Microchip

(GNSS)

was the big shot in the extended session Tuesday after the company raised its second-quarter revenue estimate because of strong product shipments.

The company ranked No. 1 on the Island most-active chart and fifth on the Instinet list. Genesis said it expects revenue for the fiscal second quarter to increase more than 40% sequentially and exceed $30 million. The company had previously forecast a sequential revenue increase of 16% to 20%. Shares of Genesis were up 28.6% to $25.34 on Instinet, and the stock rose 25% on Island.

Technology stocks were hit in the regular session and were mixed in after-hours trading. The typical tech names were dominating the most-active lists in extended trading, as five out of the top six volume movers on Instinet in the first 30 minutes of action were all part of the regular cast.

Cisco

(CSCO) - Get Report

, the top mover, was up 0.4% to $13.62, while

Microsoft

(MSFT) - Get Report

, number four on the list, inched up 0.3% to $54.50.

Juniper Networks

(JNPR) - Get Report

was the second most-active stock and was off 1.1%, after losing 13.7% in the regular session. Next was Intel, which gained 0.1% to $23.50.

Dell

(DELL) - Get Report

and

Sun Microsystems

(SUNW) - Get Report

both posted small percentage gains, while

Oracle

(ORCL) - Get Report

was slightly on the downside.

Volume remained pretty low, as 3.3 million shares changed hands in the first 50 minutes of trading. The Instinet top 20 movers accounted for 1.47 million shares.

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 whenthe sun goes down in Investing Basics: NightOwl, a section devoted to after-hours trading.