In the do-it-when-no-one's-looking column,

Arbinet

, an online marketplace for buying bandwidth, pulled its S-1 this afternoon at two minutes before 5 p.m. EDT. At least, that's the time stamp that the document had at filing site

Edgar Online

.

Alex Mashinsky, Arbinet's founder and vice president, didn't immediately return a phone call seeking comment on the pulled red herring. But Michelle Strykowski, a spokeswoman for B2B incubator

Internet Capital Group

(ICGE)

, an Arbinet investor, said the company pulled the filing in order to concentrate on its business.

Four days ago, an ICGE exec -- as if anticipating the Arbinet move -- said a comatose IPO market could be a good thing for ICGE.

Today, Strykowski had a different spin for the Arbinet news: "The IPO process puts pretty strict restrictions on a company's communications. Arbinet is trying to execute on its business model, and needs to market its success to continue to vie for a competitive position." When companies file to go public, they enter a "quiet period" for making public statements. In its filing to pull its S-1, Arbinet cited "market conditions" as its reason for withdrawing the document.

Arbinet isn't the first B2B exchange to pull its S-1 in recent weeks. Both

Impresse

and

Noosh

, two high-profile B2B start-ups with public aspirations, also pulled their IPOs in recent weeks. They are not ICGE companies.

"The hurdles have gotten higher for taking companies public," said Patrick Walravens, an analyst at

Lehman Brothers

who rates Internet Capital Group a buy. His firm has performed underwriting for ICG.

With the window for B2B public offerings becoming nailed shut tighter and tighter,

TheStreet.com

looked at Internet Capital Group's prospects in a story earlier this week. The company has invested in excess of $1 billion in 71 B2B companies, but only seven of those companies have come public so far.

Ken Fox, ICG's co-founder, told

TheStreet.com

that a temporarily closed IPO window could very well be a good thing for the firm, as it would open up opportunities to invest in other private companies on the cheap. ICG has said it plans to deploy $200 million in cash per quarter in follow-on and new investments over the next year.

Asked Friday afternoon whether Arbinet pulling its S-1 was good for ICG, Strykowski said it was neither good nor bad news.

"As far as the impact on ICG goes, our main objective is to help our companies execute, and in this case, that's what they're doing," Strykowski said.

At least six other ICG companies are currently in registration to go public. They are

PaperExchange.com

,

LinkShare

,

Servicesoft

,

ClearCommerce

,

CommerX

and

Context Integration

.

Strykowski said there was no indication at this time any of those companies would be pulling their registrations.

As originally published, this story contained an error. Please see

Corrections and Clarifications.