Yahoo!

(YHOO)

was the volume leader in extended-session Instinet trading, but the stock was ticking lower following the Internet portal's earnings and outlook.

Shares of Yahoo! were recently down 0.5% to $18.35, but they had been higher in the first part of the extra session. For the latest first quarter, the company met analysts' estimates. Yahoo! also projected revenue for the second quarter and full year that would top the current consensus expectation published by First Call.

Overall, trading activity remained a little on the light side, with around 2 million shares changing hands among the top-20 Instinet volume movers in the first hour of extra action.

Rambus

(RMBS) - Get Report

was climbing 5.3% to $7.90 after the company said revenue and earnings for the second quarter fell from the year-ago period but still came in ahead of estimates.

Redback Networks

(RMBS) - Get Report

was gaining 7.3% to $2.78. Following the close, the company posted a first-quarter loss that matched expectations and said second-quarter revenue would be flat to slightly higher than the quarter just ended.

Cognos

(COGN)

was another big winner after the bell, climbing 7.5% to $28.10. The company reported fourth-quarter earnings that topped analysts' projections.

Among other active issues, the

S&P 500 Depositary Receipts

(SPY) - Get Report

were flat at $113.40.

Oracle

(ORCL) - Get Report

was up 0.1%, and

Cisco

(CSCO) - Get Report

was unchanged.

Intel

(INTC) - Get Report

was off 0.4%.

Research in Motion

(RIMM)

was up 0.4%, and

Immunex

(IMNX)

slipped 0.1%.

Sun Micro

(SUNW) - Get Report

was off 0.1%, and

WorldCom

(WCOM)

was down 0.8%.

Dell

(DELL) - Get Report

tacked on 0.1%.