During the first six months of the year, the Liechtensteinische Landesbank (LLB Vaduz) saw its net profit plunge 77 per cent to 13.6 million Swiss francs (USD 14.7 million, 11.1 million euros), the bank said in its earnings statement.
The result, by comparison with the outcome for the same period of last year, was hit by a number of one-time costs.
These included restructuring costs and the settlement of a long-standing tax dispute with the United States, which together set back its net profit by 58.4 million Swiss francs.
The US Justice Department and a New York District Attorney's office have been probing whether LLB had used Liechtenstein's banking secrecy practices to help US clients violate US tax and security laws.
In addition to dropping their investigation, the US authorities had agreed not to impose any fines or criminal penalties on the bank, it said.
The bank maintained in July that the agreement would have no impact on its income statement, but said it was setting aside provisions for further negotiations over a separate dispute between Washington and its Swiss wing.
Company chief Roland Matt welcomed the agreement.
"The resolution of the US taxation dispute establishes clear conditions for the LLB Vaduz, which also benefit our clients and shareholders," he said in the earnings statement.
Liechtenstein and Switzerland have traditionally been prime destinations for undeclared funds owing to their long sacrosanct banking secrecy practices.
However, as a weak global economy takes its toll, other countries, and the United States especially, have been putting their feet to the fire with demands of accountability for tax dodgers and the banks that help them.
