(Updated from 7:50 p.m. EST)

A new month began on the after-hours trading market as postclose patrons came in from the cold to heat things up in the extended trading session.

Shares of

WorldCom

(WCOM)

ended their massive slide in after-hours action. The stock recouped 6 cents, or 0.33%, advancing to $19 on

Island

ECN and gained 12 cents, or 0.65%, to $19.06 on

Instinet

after a very rough day on the market.

Earlier today, WorldCom warned that fourth-quarter earnings would fall between 34 and 37 cents a share, much lower than the

First Call/Thomson Financial

49-cent consensus. The communications company also announced plans to spin off its

MCI

consumer business. WorldCom, which hit a 52-week low today, dropped 20%, to $18.94, during the regular session. With 192 million shares traded, WorldCom accounted for approximately 10% of all volume on the

Nasdaq Composite Index today.

Postclose investors have fallen into the

Gap

(GPS) - Get Report

tonight. And even though the retailer announced a drop in monthly sales and issued muted forecasts about its third quarter, its stock was up $1.31, or 5.4%, to $25.75 on Instinet.

After the bell, the clothing manufacturer announced that

same-store sales for October decreased 2% from the year-ago period, in line with Wall Street's reduced expectations. Additionally, Gap warned that third-quarter earnings would come in below analyst forecasts.

A winner during the regular session,

MRV Communications

(MRVC)

slid in nighttime action. The networking equipment stock, which jumped 5.1% today, shed 38 cents or 0.89%, to $41.63 on Island tonight.

By contrast, shares of

Read-Rite

(RDRT)

, a manufacturer of disk-drive heads, popped $1.06, or 13.5%, to $8.94 on Island, thanks to strong fourth-quarter results and positive guidance going forward. Read-Rite reported a narrower-than-expected fourth-quarter loss and announced that it was shooting for a 20% sequential increase in revenue this quarter.

In addition, chip maker

Xilinx

(XLNX) - Get Report

found some support among the after-hours crowd after a tough session for chip stocks.

Many semiconductor stocks took a plunge today after

Morgan Stanley Dean Witter

cut ratings and earnings estimates on certain chip companies. The

Philadelphia Stock Exchange Semiconductor Index

closed down 3.8% during regular trading. Xilinx, for its part, finished behind 6.9%. But in twilight trading, the specialty chip maker gave back some of its losses after it said that sales of chips by its distributors were up. The company also announced that it was on track for strong revenue growth. Xilinx increased $2.56, or 3.8%, to $70 on Instinet and lifted $2.50, or 3.7%, to $69.94.

Finally, DSL Internet equipment provider

Netopia

(NTPA)

tumbled with the report of its fourth-quarter earnings. The company dropped $4.56, or 39.9%, to $6.88, on Instinet and fell $4.79, or 41.9%, to $6.65 on Island. This evening, Netopia reported a 13-cent loss, nowhere near Wall Street's target of a 17-cent profit, and announced that it expects a break-even first quarter.

This information is provided by Instinet, a wholly owned subsidiary of Reuters (RTRSY) . For further information, please contact Instinet at www.instinet.com.

Island ECN, owned by Datek Online, 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.