The surging popularity of gift cards during the holiday season has almost no effect on retailers' December sales, despite a widespread perception that their delayed usage hurts end-of-year results, according to an analyst report published Monday.

An analysis of estimated gift card sales and expected redemptions shows that the impact of those delayed sales is minimal, Sanford C. Bernstein analyst Emme Kozloff wrote in a note to clients.

Even in an extreme case example where Kozloff assumed all gift cards were redeemed in January, the overall sales growth for December dropped by just one percentage point, while other, less extreme scenarios showed an even smaller impact.

"Our analysis indicates gift cards will not materially impact December results and should not be used to excuse poor performance," said Kozloff.

Gift cards are fast becoming the most popular holiday presents, with more than two-thirds of U.S. shoppers expected to buy nearly five cards on average this year, according to a survey of about 17,500 consumers by accounting firm Deloitte & Touche.

The problem is that more than half of those people don't spend the full value of the gift card. That means retailers essentially have been paid upfront for goods they have not delivered.

It requires them to establish growing and open-ended liabilities on their balance sheets while not being able to book the sale until the customer comes to cash them in for merchandise.

Because those cash register receipts are delayed until January or even later, some analysts and company executives are quick to blame the gift card phenomenon for lower-than-expected December sales, Kozloff wrote.

"Sure, it's an interesting topic in that these plastic cards are changing the gift-giving process somewhat, but as investors, it is the bottom line that counts and here gift cards do not make a material difference," Sanford C. Bernstein analyst Emme Kozloff wrote in a note to clients.

Wal-Mart Stores Inc. (WMT) said December 1 that strong demand for gift cards would likely push some expected December sales into January.

And some retailers are strategically positioning themselves for an after-holiday surge in sales due to gift-card popularity, Kozloff noted. Household goods retailer Target , for one, trotted out fresh merchandise through its "global bazaar" promotion early in 2005.

"Don't waste energy on gift card analysis," Kozloff wrote in the report. "It is a timing shift, not an earnings driver."