Last week,

Ariba

(ARBA)

helped

Commerce One

(CMRC)

. This week, it'll have to help itself.

Commerce One, the business-to-business software maker based in Pleasanton, Calif., is expected to report second-quarter results Tuesday after the close. Commerce One's report will come on the heels of Ariba's

blowout report last Wednesday, which kicked off the B2B earnings parade and sent the sector's stocks, including Commerce One, on a rampage.

But investors may now expect the same sort of surprise from Commerce One. Ariba beat estimates by such a huge amount -- $80 million in revenue compared with estimates of around $50 million -- that analysts couldn't find enough cliches. Here's

Thomas Weisel Partners'

Robert Schwartz's low-key assessment: "It's probably the best quarter I've ever seen in my career. It's going to be hard to be that brilliant, for Commerce One or any other company, for that matter," Schwartz says. (He rates Commerce One a buy, and his firm has no underwriting relationship with the company.)

A Long List

Reports from other B2B companies are on the way, too. Along with Commerce One,

i2 Technologies

(ITWO)

will report on Tuesday. On Wednesday,

PurchasePro.com

(PPRO)

,

E.piphany

(EPNY)

and

Vitria Technology

(VITR)

come out. Thursday will see

Ventro

(VNTR) - Get Report

and

Viant

(VIAN)

.

Commerce One went on a tear last week, finishing the week up 79%. But that means Commerce One may take the classic buy-on-the-rumor, sell-on-the-news hit that makes Wall Street so maddening. On Monday, it finished down 8%, or 5 9/16, at 64 3/8.

"Whenever you have a stock go up 80% in one week, it's vulnerable to consolidation, but I do believe Commerce One will produce strong results," says Chris Vroom, an analyst at

Credit Suisse First Boston

who has no rating on Commerce One. (His firm has done underwriting for the company.) "Ariba's results make it pretty clear that major corporations across America are embracing B2B solutions pretty rapidly." (Vroom rates Ariba a buy, and his firm has done no underwriting for the company.)

"The same fundamentals that drove Ariba's quarter will play out in Commerce One as well," adds William Epifanio, analyst with

J.P. Morgan

, who rates both Commerce One and Ariba buys. "It's already given back some of its run-up, so maybe that will pave the way for a better pop Tuesday, should the news be good." (His firm has no underwriting relationship with either company, though it has advised Commerce One on acquisitions.)

Loss Expected

Commerce One is expected to report a loss of 13 cents a share, according to the consensus of 21 analysts tracked by

First Call/Thomson Financial

. That compares with a loss of 9 cents a share last quarter. But more importantly, perhaps, will be Commerce One's revenue number. Analysts are pegging it at around $47 million, compared with the $35 million the company reported last quarter.

But for Commerce One's stock to get a big pop out of its report, the company will have to beat the estimates by a significant margin.

Just beating the projected numbers "won't be good enough," says Mike Dubrow, an analyst at

Jacob Asset Management

, which is long Commerce One. "They'll have to have a similar kind of percentage change to Ariba. But the problem there is that you're comparing two different revenue models."

What Dubrow is referring to is the tendency of Commerce One's numbers to be back-end loaded. Because the company is setting up major trading exchanges in industries from automobiles to aerospace, the company has bet that long-term revenue will come from transaction fees levied on those exchanges.

Ariba, on the other hand, gained about two-thirds of its revenue from software licensing fees in the most recent quarter. Even though that revenue can sometimes be deferred as well, it hits the top line within a quarter or two and isn't dependent on building liquidity in exchanges. (

TSC

earlier this month wrote about the

differences in the two companies.)

Different Models

"With Ariba's software licensing model, they take more cash up front," says Dubrow, whose firm has no position in Ariba. "Commerce One, on the other hand, will take equity in an exchange, or they'll do a deal where they'll let customers pay less for the software if they get a cut of the exchange transaction fees."

In the long run, Dubrow likes that model. But he concedes Ariba's stock may outperform in the short term.

In a recent report,

Dresdner Kleinwort Benson

analyst David Garrity puts a number on what Commerce One needs to do so it won't pale in comparison with Ariba.

"For CMRC to match ARBA's impressive sequential revenue growth of 101%, the company would have to deliver almost $71 million on the top line," writes Garrity, whose firm has done no underwriting for Commerce One. He rates the stock a buy. "Given the intense rivalry between the two companies, we believe the Street would be disappointed with anything less than this figure."

Analysts also will look for more information from the company on its

partnership with

SAP

(SAP) - Get Report

, as well as its pending acquisition of consulting firm

AppNet

(APNT)

.

While analysts almost uniformly praise the acquisition because it allows Commerce One to deploy consultants to install its software at will, the deal has raised questions over Commerce One's long-term gross profit margins. It will add 1,000 consultants to Commerce One's payroll. Those numbers likely won't be included in this quarter's earnings.

"Eventually, when you take into account the AppNet deal and the SAP numbers, revenue numbers on Commerce One will go up substantially," says Patrick Mason, an analyst with

E*Offering

, who rates the company a strong buy. (E*Offering has no underwriting relationship with Commerce One.) "Then everyone will have new estimates and be able to value Commerce One on that."

Commerce One still lags behind Ariba when it comes to valuation, though it's made up a lot. After Commerce One's huge spike last week, it's trading at 122 times trailing revenue, while Ariba trades at 136 times.

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

Corrections and Clarifications.