(Reuters) - HSBC Holdings Plc (HSBA.L) might pay a fine of $1.8 billion as part of a settlement with U.S. law-enforcement agencies over money-laundering lapses, according to several people familiar with the matter.

The settlement with Europe's biggest bank - which could be announced as soon as next week - will likely involve HSBC entering into a deferred prosecution agreement with federal prosecutors, said the sources, who spoke on condition of anonymity.

The potential settlement, which has been in the works for months, is emerging as a test case for just how big a signal U.S. prosecutors want to send to try to halt illicit flows of money moving through U.S. banks.

An HSBC spokesman said: "We are cooperating with authorities in ongoing investigations. The nature of discussions is confidential."

HSBC Criminal Law Investment