Swiss-based UBS AG will withhold approximately $282 million in deferred pay that executives would have received, marking the first time the bank’s bonus claw-back mechanism has been triggered by a loss, Bloomberg reported.

UBS introduced last year a plan that would pay 900 million Swiss francs ($341 million) to managing directors, executive directors and directors in equal parts in 2010, 2011 and 2012. The lender yesterday posted a 2.74 billion-franc loss for 2009, compared with a loss of 21.3 billion francs for the previous year.

“The critical condition, a net profit for 2009 according to International Financial Reporting Standards, was not met,” UBS CEO Oswald Gruebel said in a memo to employees dated yesterday.

Politicians are stepping up pressure on banks to curb bonuses after pumping in trillions of dollars to bail out firms during the credit crisis. Zurich-based UBS received a 6 billion- franc investment from the Swiss government after amassing more write-downs and losses than any other European lender. The government sold its stake in August, earning a 1.2 billion-franc profit.

UBS is paying out 2.9 billion francs in cash bonuses for 2009, 34 percent more than the previous year. The bonus pool was cut by the decision to defer a greater proportion of variable compensation into future years, Chief Financial Officer John Cryan told analysts and reporters yesterday.

UBS yesterday posted its first quarterly profit in more than a year, helped by lower charges on its own debt and a tax credit. Gruebel, in the memo, reiterated that profit targets announced in November for the next three to five years, including reaching an annual pretax profit of 15 billion francs, are “realistic” and “reachable.”