BERLIN (AP) — Switzerland's former finance minister says he believes the stress of bailing out the country's biggest bank, UBS AG, caused him to suffer a heart attack.

Hans-Rudolf Merz was finance minister from 2003 to 2010. He suffered the heart attack at the height of the financial crisis in 2008 as Switzerland embarked on the bailout of UBS, which was hit by massive U.S. subprime mortgage losses.

Merz told Wednesday's edition of Swiss daily Neue Zuercher Zeitung that he was fit at the time and believes the heart attack resulted from "momentary overloading due to the UBS rescue."

He said he'd learned on the day it happened that authorities might have to provide some $60 billion in guarantees.

Merz said: "I hadn't expected this immense sum. That simply knocked me over."