Updated from 5 p.m. EST

Cisco ( CSCO) was the undisputed volume leader in extra trading Wednesday, but investors, after initially bidding up the stock, were bailing out as the company's post-earnings conference call progressed.

Even before the earnings press release came out following the close of trading, investors knew the maker of switches and routers would beat estimates. In the first hour of extended trading Cisco climbed around 4%.

Lately however, Cisco was losing 7.6% to $17.20 on Instinet. The company posted second-quarter earnings of 9 cents a share. Analysts were expecting earnings of 5 cents. Sales fell to $4.8 billion from $6.7 billion in the year-ago quarter, but the top line rose 8% sequentially.

WorldCom ( WCOM), which will report its quarterly results Thursday, was unchanged at $6.69. The Nasdaq 100 Unit Trust ( QQQ) was up 1.1% to $36.43. Ciena ( CIEN) was climbing 2% to $9.20.

Tyco ( TYC) was flat at $25.92 after gaining 12.2% in regular trading. Halliburton ( HAL) was ticking up 0.3% at $13.05, and Sprint PCS ( PCS) was inching up 0.2% to $10.02.

Intel ( INTC) was rising 1.2% to $33.30, and Sun Micro ( SUNW) was ahead by 1.4% at $9.71. Xilinx ( XLNX) was up 2.2% to $41.05.

Elsewhere, Mercator Software ( MCTR) was gaining 4.2% to $5.20 after the company posted a profit, before items, for the fourth quarter. Including items, the company lost 26 cents.