Updated from 5:13 p.m. EDT

Trading was heavy in after-hours trading Tuesday as more then 5 million shares changed hands in the first 15 minutes of action, but volume dropped off considerably after the initial flurry.

The extended session was an extension of the regular session, which produced minimal overall change. Most stocks on the Instinet top 20 volume movers moved less than 1%.

Shares of

Redback Networks

(RBAK)

were getting hit hard, falling 14.5% to $2 on Island ECN, after the company projected third-quarter revenue of $35 million to $40 million. Analysts were expecting a top line of $54 million.

Amazon.com

(AMZN) - Get Report

was off 1.3% to $7. The company has come under some heat in recent days as

fears spread that the company's business will suffer if consumers continue to pull in their spending.

Genesis Intermedia

(GENI)

was off 6.8% to $5.50 on Instinet, after falling 32.9% during the regular session. Earlier in the day, the direct marketing company said the postponement of a 3-for-1 stock split hadn't been discussed in some news reports.

WorldCom

(WCOM)

was up 0.1% to $14.34, after gaining 5.3% in the regular session. The company confirmed on Tuesday that it has bid $40 million for some of the assets of

Rhythms Netconnections

. The move is an effort to make sure WorldCom's Internet service is not disrupted by the demise of the Rhythm network, a unit of Rhythms Netconnections.

The big tech names were also making the rounds on the charts.

Intel

(INTC) - Get Report

was the top Instinet volume mover, but remained unchanged at $21.68. Boxmaker

Dell

(DELL) - Get Report

, which fell 0.3% to $19.10, was next.

Oracle

(ORCL) - Get Report

was up 0.2% to $12.27.

JDS Uniphase

(JDSU)

remained unchanged at $6.59.

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.