As much as $50 billion in cash is on its way back to Federal Reserve banks this week after the year 2000 rollover failed to trigger panic hoarding by consumers.

Banks across the country are preparing to ship back the cash--much of it never opened from its shrink-wrapped packaging--in armored trucks to 37 Federal Reserve offices. In recent months, the Fed had pumped the cash into the banking system to handle any unusual cash demands at the end of the year.

Fed officials said they did not know yet exactly how much consumers withdrew. But while withdrawals were slightly higher than normal for this time of year, they were not nearly as high as they had expected, federal officials and bank executives said.

A few customers demanded large withdrawals that essentially emptied or would have emptied their accounts. At one bank, which asked that its name not be used, a customer in Virginia wanted to withdraw $500,000 on Dec. 31, but the bank was able to convince him that it wasn't necessary.

"There was ample cash [nationwide] and people didn't take it out," said Federal Reserve Board spokeswoman Lynn Fox. "That implies that people were very calm."

The Fed distributed about $80 billion in the fourth quarter of 1999, compared with $23 billion over the same period last year. Some of the $57 billion in additional currency would have been needed anyway because of the strong economy and record holiday shopping. But a large portion of the additional cash shipments were "Y2K-related," said another Fed spokeswoman, Rose Pianalto. If stretched out in $1 bills, the $80 billion would reach around the earth 311 times, Treasury Department officials said.

Fed officials are also unsure how much unneeded Y2K cash will be returned by the country's approximately 21,000 financial institutions. The Fed is extending hours at its receiving docks to accommodate additional armored trucks carrying the cash.

"A lot of it didn't even get into the system at all," said Fed spokeswoman Pianalto. "It just sat in vaults."

An approximation of how much cash Y2K worriers withdrew will be available Thursday when the Fed's weekly Wednesday-to-Wednesday report on currency demand comes out. Banking institutions are already saying the figure will not be large.

For security reasons, bankers will not disclose exactly how much extra money they have had on hand. But officials at First Union Bank in Charlotte expected the average consumer to withdraw $150 to $200 in the days before Jan. 1. That would be $50 to $100 more than normal on a holiday weekend.

In fact, withdrawals averaged $120 on Dec. 30 and $130 on Dec. 31, an amount that meant the bank didn't even have to draw on extra reserves stockpiled for Y2K, said First Union spokeswoman Christy Phillips.

Suntrust of Atlanta, whose Crestar subsidiary has the largest number of consumer deposits in the Washington area, had "hundreds of millions" of extra cash on hand but used "much less than 10 percent of it," said spokesman Tony Mattera.

At Citibank, the nation's second-largest bank, withdrawals didn't exceed what would be expected for a long holiday weekend, said Citibank spokeswoman Susan Weeks, who spent much of Monday at the company's credit-card processing plant in Hagerstown.

Bank of America, which has 5,000 branches and 14,000 ATMs nationwide, was ready for a cash run, said Torod Neptune, a bank spokesman. "We had to use some of the [extra] money, but not as much as we expected. As we got closer to the end of the year, we saw people getting less skittish" about Y2K.

Chase Bank said it had extra cash on hand "just in case," but did not notice any difference in additional transactions.

Any cost incurred by keeping cash on hand instead of invested in an interest-earning project was shrugged off by bankers yesterday.

"Bankers would say it was money well spent because it caused the public to take a common sense approach," said John Hall, spokesman for the American Bankers Association.

But there were a few minor scares.

On Dec. 30 two small credit unions asked the Federal Reserve for emergency cash as a precaution and on Dec. 31 a larger bank did so, Fed officials said. The officials would not reveal the names or locations of the institutions but stressed that at no time did any institution even come close to running out of cash.

"Some of them had very small vaults and could only hold so much," Pianalto said. "They did have a Y2K demand and they were afraid that if they didn't get some more [currency] they would have more of a demand on the weekend and wouldn't be able to meet it."

AMPLE RESERVES

By federal law, every U.S. bank must have a certain amount of money on reserve deposit with the Federal Reserve, the nation's top bank regulator. The amount required is determined by regulation and depends on the size of the bank and other factors. The amount is about 10 percent of a bank's checking and demand deposit accounts.

Reserves, which do not earn interest, can be held:

* As cash in a bank vault.

* In an account at one of the 12 Federal Reserve banks.

Banks that were able to fulfill all their anticipated extra cash needs for Y2K with their required federal reserve deposits--that is, by converting all reserves to vault cash in bank branches--incurred little if any cost in keeping more cash on hand. Those whose cash requirements exceeded their required federal reserve deposits did incur extra costs--they had to keep cash on hand that otherwise could have been invested. But bankers say preserving consumer confidence has been worth any increased costs.

CAPTION: A worker sorts money yesterday at the Federal Reserve Bank of Cleveland. Withdrawals were higher than normal this year but not as high as expected.

CAPTION: Gene Allred, head of Bank of America's local branches, in front of the bank's downtown offices yesterday. The bank said it was ready for a run on cash.