Enron

(ENE)

remained the most active stock in after-hours trading Tuesday, following a day in which the

issue lost 85% of its market value.

The stock plunged in regular trading to 61 cents after Enron's debt was downgraded

to junk status and

Dynegy

(DYN)

called off its plan to acquire the energy merchant. Enron was the top volume mover on Instinet, where it traded up 6.6% to 65 cents. On the Island ECN, the stock was also the most actively traded and climbed 4.8%.

Overall, volume was heavy on Instinet. In the first 30 minutes of trading, about 4.6 million shares changed hands among the top 20 volume movers.

Pharmacyclics

(PCYC)

made its second consecutive appearance on the volume leader board, but was unchanged from the 4 p.m. EST close of trading at $25.34.

Conexant Systems

(CNXT) - Get Report

was also active on Instinet, where the stock tacked on 0.2% to $15.10.

Brocade

(BRCD)

was losing 1.4% to $28.41 in extra trading. After the close, the company posted fourth-quarter earnings, excluding items, of 5 cents a share, a penny ahead of Wall Street's expectations. Revenue totaled $116.5 million.

The

Nasdaq 100 Tracking Stock

(QQQ) - Get Report

was inching down 0.1% to $38.73.

Cisco

(CSCO) - Get Report

was up 0.1% to $18.90, and

Sun Micro

(SUNW) - Get Report

was off 0.2% to $13.13.

Oracle

(ORCL) - Get Report

was gaining 0.4% to $14.18, and

WorldCom

(WCOM)

was up 0.1% to $14.39.

BioReliance

(BREL)

, which provides testing and development services to biotechnology and pharmaceutical companies, was one of the extended session's biggest winners, trading up 10.9% to $28.89.

Palm

(PALM)

was up 5.9% to $3.61. The company said after the close that it expects to report second-quarter revenue of $250 million to $280 million, with a loss, excluding items, of about 7 cents a share. Analysts are looking for a loss of 7 cents with a top line of $232.1 million.

Also after the bell,

FreeMarkets

(FMKT)

forecast fourth-quarter revenue and fees of $44.7 million to $46.7 million and operating earnings of 5 cents to 9 cents a share. Analysts are calling for earnings of 2 cents on a top line of $42.9 million.

Microsemi

(MSCC)

was losing 5.1% to $30.58 in late trading after the company posted fourth-quarter earnings of 17 cents a share, before items. The bottom line beat the consensus estimate by a penny. For the first quarter, the company expects sales to increase as much as 2% from the fourth-quarter level of $57.2 million.