Their portfolios are comparable in size. They are in similar businesses.

But HSBC Holdings Plc has a deal to sell its $30 billion of private-label credit cards assets to Capital One Financial Corp., while Citigroup Inc. has been holding the bag on $45 billion of retailers' credit card loans for more than two years.

Citigroup sought to jettison its portfolio, which includes cards issued on behalf of Home Depot and Sears, along with other assets it tagged noncore after the crisis.

The reason why Citigroup's portfolio has yet to sell, industry analysts explained, is because it is priced too high.

"The universe of potential buyers is very finite for private labels," said Robert Hammer, chief executive of consulting firm R.K. Hammer in Los Angeles. "It's a different animal. It's a different creature. It's a different type of credit" from general purpose Visa- and MasterCard-branded cards.

It is unclear exactly how much Citigroup is asking, but it is evidently a lot more than the 8.75% premium, or $2.6 billion, that HSBC accepted as it seeks to bind its own crisis wounds and narrow its focus.

Capital One "got a fire-sale price on it," said Brian Riley, a research director in the bank cards practice at TowerGroup. "This is an affordable one for them. It's not going to overwhelm them. Capital One couldn't buy a Citi without getting itself into trouble."

The deal, announced Wednesday, includes HSBC's MasterCard, Visa, private-label and other credit card operations. Best Buy, Neiman Marcus and Saks Fifth Avenue are among its private-label customers.

HSBC Bank USA's $1.1 billion credit card program is not part of the deal; HSBC's U.S. unit will continue to offer credit cards to its customers.

HSBC said that the businesses it is selling produced $600 billion of profits after tax at June 30 and that they had gross assets of $30.4 billion.

Under the agreement, Capital One may pay in cash, or with a combination of cash and common stock, but the maximum value of the stock portion would be $750 million. Capital One said that such a stock payment would be worth $39.23 per share, the average of its closing prices on Monday and Tuesday.

Capital One will need to raise additional capital, perhaps as much as $1.25 billion, the company said.

It faces integration challenges, too. There will inevitably be some overlap in business, Riley said. "They have to decide should they keep those dual lines," said Riley. "They are going to burn off a lot of the accounts quickly."

Regulatory approvals are required, and either side may back out of the deal if it has not closed by May 10.

A Capital One spokeswoman did not return calls before deadline.

The deal was not a huge surprise. In a June note to investors, John Stilmar, who follows credit card issuers for SunTrust Robinson Humphrey in Atlanta, alluded to the possibility of the move.

"With multiple private label portfolios lingering in the market, as well as several depositories …looking for buyers, the choices available to [Capital One] … indicate to us that [it] is prepared to go on the offense in a meaningful way," Stilmar wrote.

As for Citigroup, the bank might be considering changing its mind on the attractiveness of private-label cards.

The Financial Times reported last month that improving credit conditions are causing the banking company to reconsider the business.

A Citi spokeswoman said she could not talk about the possibility.

Still, experts agreed, Citi could still part with for the right price — provided it lowers its expectations.

Dean Anason contributed to this article.