ach year, immigrant workers send $30 billion to relatives back home, a ritual that has spawned a flourishing industry dedicated to transferring cash from the United States to just about anywhere in the world.
But Sept. 11 cast that dollar lifeline in a new light — as a potential pipeline for terrorist financing — and the once informal business now faces significant changes.
The government has now imposed strict new controls on the companies that handle nearly all immigrant payments, transforming a business that thrived on its lack of paperwork and catered to people who could not, or would not, do business with banks.
Some of the new federal rules were put in place this summer and others are expected to be issued in the next few months. They have already caused money transmitters to automate their businesses, report even small cash transfers to federal law enforcement authorities and demand proof of their customers' identities.
Anyone who sends money overseas now must be checked against government lists of suspected money launderers and terrorists, a task that also requires money transmitters — many of them storefront operations — to undergo training to spot suspicious movements of money.
"As I tell the companies, the party's over," said Michael R. McDonald, a retired Internal Revenue Service special agent who advises banks and money transmitters on how to comply with the array of new regulations.
Filipino workers who send money home — from all over the world, they send $6 billion a year — have already seen a change. When they go for the first time to one of the 60 Lucky Money outlets across the country, they must show a government- or employer-issued ID.
"We never asked for ID before," said Robert Reyes, the vice president of the California-based company, which specializes in home delivery of cash in the Philippines. "But Sept. 11 made us all more cognizant."
So far, no one has balked at showing an ID, and Mr. Reyes doubts that most of his customers would.
"These small customers, all they do is work, work, work in order to generate some revenue for relatives back home," he said.
Some immigrants, though, do worry that closer government scrutiny of money transfer companies could mean that the Immigration and Naturalization Service might track them down.
"I have a passport that I can show, but what if they look at more than my name?" said a Tibetan woman named Chunta, a Brooklyn resident who overstayed her tourist visa long ago and regularly sends cash earned as a store clerk to relatives in India.
Treasury Department officials, who administer the new federal regulations, have said people making ordinary transfers should not be worried.
State Banking Department officials, however, began sharing money transfer information in March with the local office of the F.B.I. All names of customers are checked against lists of suspected criminals.
The amount of data involved is huge: in the first six months of this year, money transfer companies handled an average of 160,000 transactions a day just in New York State.
Elizabeth McCaul, the state's superintendent of banks, has also pressed transmitters to get personal data from each customer, although the federal regulations requiring that have yet to be issued.
She said the transmitters should get a birth date verified by official documents, and as much information as possible about the foreign recipients. Transmitters also have to make sure they do not handle the business of anyone listed as a terrorist by the federal Office of Foreign Assets Control.
All of this is new territory for many companies, which generally never asked immigrants for identification unless they brought in a large amount of cash to be sent overseas.
"We've had people call here asking for help and they didn't know what O.F.A.C. is," said Jorge A. Guerrero, president of the 27-member National Money Transmitters Association.
There are also many reservations about the effectiveness of new controls for spotting terrorist money.
The first of the new regulations subjected money transmitters, currency exchanges and check-cashing stores to the same antilaundering rules that banks have followed for 16 years. That meant they must now report suspicious cash transactions above a threshold value: $5,000 for banks and, now, $3,000 for money services businesses like transmitters.
Setting thresholds was intended to catch drug traffickers or criminal groups that have a lot of money to disguise or move quickly. Terrorist groups, investigators say, are more likely to move small amounts of money intermittently.
To increase the chances of discovering a criminal who sends money through different companies, 20 small and medium-size remittance companies also voluntarily pool their customer records.
"We wanted to prove that these are not conduits for money laundering," Mr. Guerrero said. "These are people who have a real stake, who can show that it's a real industry and provides a real service."
It is a constant struggle. It has become even more fierce in the past year as American banks have moved aggressively to capture the lucrative remittance market which, according to Inter-American Development Bank studies, generates an estimated $2.4 billion in fees a year.
Many money transmitters say their banks have even closed their accounts, saying the independent cash transfer business is too expensive to service.
Without a regular bank account, a transmitter cannot do business.
Those specializing in cash transfers to south Asia and the Middle East have been especially hard hit.
"Some banks are discriminating," said Kamal Ahmed, president of Placid Express in Astoria, Queens, which sends remittances to Pakistan and Bangladesh. "I have a license, and I follow all the rules from the federal government and the State Banking Department. The banks are dealing with others, but they have closed our accounts."
The vulnerability of the international networks that move cash was demonstrated by the Sept. 11 hijackers.
Over three days just before the attacks, two of the terrorists transferred about $15,000 to one recipient in the United Arab Emirates, dividing the cash into four transactions and using different Western Union outlets.
The men's names were not on a watch list at the time. A Western Union official refused to comment on whether the recipient of the closely spaced wire transfers should have set off an alarm.
"We don't talk about specific customers," said David T. Wittman, the company's compliance officer. "But the way the reporting regime is set up, there are red flags."
In the absence of any law requiring companies to pool information, officials conceded, it may still be difficult to follow the terrorist money trail.
"As a practical matter, I could still go to three different companies and wire money to, say, the United Arab Emirates," said a Treasury official, speaking on condition of anonymity. "But there still has to be some overarching regulatory mechanism."
The biggest concern for the millions of immigrants sending cash overseas will be the Patriot Act requirement that businesses including banks and money transmitters verify their customers' identities and backgrounds.
Many of the immigrants who are the core market for money transfers do not have drivers' licenses or other government-issued ID's. Or, even if they are here legally, they reflexively fear exposing themselves to the authorities.
Businesses that cater to them have adjusted to those circumstances, but their methods may no longer pass muster.
Abacus Federal Savings Bank, a Manhattan-based bank that serves Chinese immigrants, handles about 10,000 cash transfers to China each month, averaging $2,000 to $3,000 each.
One of every five of those customers has no proof of identity, said Thomas Sung, the chairman of the bank.
Rather than have them send money through someone else's bank account, a method that eliminates any hope of tracing the source or true recipient, Mr. Sung said, he encourages immigrants to open a bank account.
"Just because they don't have ID's doesn't mean they are not law-abiding persons," Mr. Sung said. "So this is a risk we're willing to take for the time being because we are a community bank. If the regulations say I can't do it, then it's going to cost me business and cause a tremendous inconvenience for those who don't have or don't want to show any ID."