A U.S. Treasury Department initiative to curtail money laundering through all-cash real estate transactions will expand to all applicable home and condo sales in Suffolk and Middlesex County, according to a news release from the department. The news comes after what began as a pilot program by the Treasury’s Financial Crimes and Enforcement Network (FinCEN) in New York City and Miami was gradually broadened to more cities. It’s also another sign that federal legislators could soon draft a bill that would make it much more difficult to purchase residential real estate anonymously in the United States.

Since 2016, when FinCEN’s new all-cash disclosure rules were first implemented and later expanded to most large metro areas in the country, the agency says it had acquired “valuable data on the purchase of residential real estate by persons implicated, or allegedly involved, in various illicit enterprises including foreign corruption, organized crime, fraud, narcotics trafficking, and other violations.” Adding more locations to the list and further revising its oversight rules “will further assist in tracking illicit funds and other criminal or illicit activity, as well as inform FinCEN’s future regulatory efforts in this sector,” according to a FinCEN press statement.

The new disclosure requirements apply only to home or condo transactions in which the buyer is financing the purchase with cash, and if that buyer is an LLC or trust rather than an individual. These transactions are not illegal, but under FinCEN rules, the identities of the people who own the LLC or trust would need to be disclosed and verified by regulators. In a previous update to the all-cash disclosure rules, FinCEN also lowered the price threshold that triggers the rules to $300,000.

Data on illicit funds funneled through real estate is scarce, although researchers and lawmakers including Florida Senator Marco Rubio have called it a major issue in many markets. It’s also unclear what impact, if any, FinCEN’s disclosure rules will have on the housing market, in the Boston area or elsewhere. A study examining the effects of the rule in Miami and other cities where the rules were first implemented found a small decrease in the rate of home price appreciation among the high end of the luxury market.