Wild.

Warrants in

Adatom.com

(ADTM)

were the most actively traded substance on

Island

ECN and were the seventh most-active options on

Instinet

. Interest in the company's options opened tonight's session with a bang, passing a half-million shares traded within the first 30 minutes of action on Island.

Why?

Well, that's a really good question. Today, Adatom.com's common shares gained 1 5/16, or 19%, to 8 5/16. That's a sizable pop, but it could've been even better -- earlier Adatom.com hit a 52-week high of 10 3/4 and opened the session at 10 1/2. Warrants charted a similar path, gaining 1 7/32, or 85%, to 2 21/32, hitting 52-week high of 3 7/16 right after the open.

Tonight's interest was momentum in the wake of Adatom.com's announcement about an agreement with the

China Product Trade Net Center

, or CPTNC. The CPTNC is an organization created with the support of the Chinese government to promote the distribution of Chinese goods using the Internet as a primary means of accomplishing this end. According to a company press release, Adatom.com and the CPTNC will create a joint-venture company based in Beijing to help support the Internet execution of the CPTNC's business-to-business goals.

Pavlov was wrong. A ringing bell doesn't cause salivation -- the words "China" and "business to business" do.

As a result, warrants in Adatom.com rose 11/16 to 3 5/16 on 1.4 million shares on Island and 53/64 to 3 31/64 on 72,000 shares on Instinet. According to a company spokesman, these warrants have a strike price of $6.50 and expire in October 2002. They can be called in at $9.10.

So what does that mean?

It means that one warrant entitles the holder to buy one share of Adatom.com for $6.50 at any time before October 2002. That means a warrant bought at 3 would make Adatom.com's stock worth $9.50 after adding in the strike price. But if Adatom.com spends 20 days above $9.10, then the warrants can be called in, which means the holder gets no money and no shares. That's a fairly unlikely scenario however. Most people with half a brain would either sell their warrants or cash them in, rather than get stuck holding a worthless stack of paper.

There's always room for Jell-O, or if you're

Microsoft

(MSFT) - Get Report

, additional gains in the wake of a huge day-session vault.

Mister Softee, which rose 8 5/8, or 8%, to 111 7/8 on

news that a settlement might be nearing in its antitrust case, gained 1 1/8 to 113 on 252,000 shares on Instinet and 1 5/8 to 113 1/2 on 45,000 shares on Island.

In other late night large-cap moves:

Cisco

(CSCO) - Get Report

edged higher, gaining 27/64 to 78 17/64 on 215,000 shares on Instinet and 5/8 to 78 3/8 on 52,000 shares on Island. This tops a day-session gain of 5 5/8, or 8%, to 77 13/16.

Yahoo!

(YHOO)

, part of an Internet sector that faltered in the final hours of trading, recovered 1 to 192 on 67,000 shares on Instinet after falling 3% during the day.

MicroStrategy

(MSTR) - Get Report

, still smarting from Monday's 140-point smackdown, continued the recovery program, gaining 6 1/16 to 124 on 38,000 shares on Island after jumping 29 to 117 3/4.

Intel

(INTC) - Get Report

continued sliding, dropping 1 7/8 to 140 3/4 on Instinet after falling 1 7/16 to 142 5/8 during the day.

Everyone likes a quick

Wit

(WITC)

. Especially investors.

Tonight, Wit Capital Group flew up 3 13/16 to 20 5/16 on 100,000 shares on Island and 3 9/16 to 20 1/8 on 143,000 shares on Instinet after announcing that its first-quarter results would crush predictions. According to a

First Call/Thomson Financial

TheStreet Recommends

estimate, Wit was expected to lose 5 cents a share in the first quarter vs. last quarter's 67-cent loss.

The company said it would outpace analyst picks on the strength of its recent merger and favorable market conditions, turning a profit for the first time ever. Finalized details about the quarter will be released during the week of April 17.

Ahead of

the news, Wit gained 9/16, or 4%, to 16 9/16.

Biotechs got funky with the postclose moves.

After taking a cue from

Curtis Mayfield

, gettin' on up during the day,

Immune Response

(IMNR)

and

Immunomedics

(IMMU) - Get Report

took a cue from

James Brown

and got down at night.

Immune Response eased 3/16 to 15 7/16 on 147,000 shares on Island after gaining 4 11/16, or 43%, to 15 11/16. The huge pop came on news that Immune Response's drug Remune, which boosts immune systems, might be effective in inducing HIV immunity.

The results of a clinical study were presented at a conference in Bangkok, Thailand. In the study, 297 HIV infected patients were either given Remune or a placebo over a 40-week period. T-cell counts were higher in those patients that took Remune.

Immunomedics dropped 11/64 to 28 3/16 on 110,000 shares, coughing up just a little of today's 6-point jump to 28 1/2.

This company moved on news that it received a patent covering its techniques to detect lesions and tumors related to cancer, infections and blood clots. The patent, with the snappy title "Intraoperative, intravascular and endoscopic tumor and lesion detection, biopsy and therapy," is an extension of an earlier Immunomedics' patent.

H. Wayne Huizenga has more than just the

Miami Dolphins

, Pro Player Stadium and an initial starting his name. As of 4 p.m. EST, he also had a chunk of change invested in

ZixIt

(ZIXI) - Get Report

, an Internet encryption company.

Halted pending news at 3:15 p.m., ZixIt delivered just after the bell, announcing that Huizenga will invest between $20 and $44 million in the company, becoming vice chairman of ZixIt's board in the process. The deal hasn't been made official yet, pending approval from ZixIt's board.

Investors got excited about Huizenga, who founded

Waste Management

(WMI)

in the 1970s and is probably best known for

Blockbuster Video

(BBI) - Get Report

, a company he helmed before selling it to

Viacom

(VIA) - Get Report

for $8.5 billion in 1994. Tonight's announcement reunites Huizenga with David Cook, ZixIt's chairman and CEO, who was instrumental in developing Blockbuster's business systems.

ZixIt, which is not easy on the tongue, went easy on the brakes after resuming trading at 4:49 p.m. It gained 12 7/8 to 88 on 27,000 shares on Island after jumping 14 1/8, or 23%, to 75 7/8 during the day session.

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 8 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.