Shareholders may deny UBS' board and management approval for their oversight of the wealth manager in 2018 as a result, the chairman cautioned. The vote is a peculiarity of Swiss securities law, generally waved through by shareholders, which exempts managers from liability for their actions.

Languishing Stock

Since many investors plan to abstain, UBS may not the 50 percent approval that is necessary. «Against this backdrop, this isn't a given», Weber cautioned. The last time shareholders denied UBS approval was in 2008, when the bank was bailed out by the Swiss government.

Another vulnerable spot for the duo, which has run the bank together since 2012, is a languishing stock price. «We're not alone in this fate», Weber said. The banking industry had generally suffered a setback on its valuation. «But of course we are not happy and unfortunately – despite our advances – we had a setback in France».

Highest-Paid European Banker

Ermotti is expected to spend much of the investor meeting, which begins at 10:30 a.m. CET, justifying his 14.1 million Swiss franc ($13.9 million) payday last year. Chairman Weber unfurled an unconventional line of reasoning to explain the pay for Ermotti, who is the highest-paid banker in Europe.

«UBS is a global bank with Swiss roots. We can't simply consider salaries in Switzerland, we're also competing with other global banks for talent», Weber said. In addition, for the time that he and Ermotti have run the bank, shareholders have received more in payouts than staff has in bonuses.

Ermotti himself said he takes the criticism of his salary coolly. «I accept that some people are against the sum in principle. That's fine.» Others, he said, have other reasons for griping. «Some people are not really informed or are perverting facts.»