In a highly critical report, U.S. proxy advisor Institutional Shareholder Services (ISS) said it recommended investors do not ratify management's work last year when asked to do so at an annual shareholder meeting on May 23.

"At a certain point, shareholders should make their concerns heard," it said, singling out lax money laundering controls and the group's "precarious" low share price, which it said threatened "Deutsche Bank's very existence".

"It is time for shareholders to hold the bank personally responsible," ISS said, adding that "underlying patterns of leadership and the culture of risk" had not improved despite many promises to do so.

Deutsche Bank's management, under the watch of chairman Paul Achleitner, has faced renewed criticism amid dwindling profits and strategic uncertainty, underscored by the recent collapse of merger talks with Commerzbank.

A second advisory group, Glass Lewis, has also urged investors not to endorse management's work, citing a substantial loss of shareholder value and performance concerns.

Deutsche Bank said the ISS recommendations did not reflect the current situation at the bank.

"While we acknowledge that there is still work ahead of us, we have significantly improved our risk and control systems in the last three years and we will continue to do so", it said.

It is uncertain which way shareholders will vote but a vote of no confidence would deliver a powerful symbolic rebuke to management, although there are no legal repercussions.

Following similar advice from advisors, shareholders in German drugmaker Bayer recently voted against approving the work of management after the costly takeover of seed maker Monsanto led to a slump in its share price.

UBS shareholders also refused to endorse the performance of the Swiss bank’s leadership last week, following the bank's French conviction for helping wealthy clients evade taxes.

The ISS report paints a bleak picture of attempts to turn around the lender, which has been fined billions of dollars in numerous cases, including a penalty for artificial trades between Moscow, London and New York that authorities said were used to launder $10 billion out of Russia.

"While Deutsche Bank has been promising to clean up its internal controls for many years, alone in 2018, a slew of new investigations were launched against the bank for failure to have appropriate anti-money laundering ... controls," ISS said.

It added that Deutsche Bank's financial viability had further deteriorated, making it a potential takeover target."

Deutsche Bank's share price has lost more than 70 percent and the lender has been through three chief executives since Achleitner became chairman in 2012.

Last month, Deutsche and Commerzbank, Germany's two largest lenders, announced that nearly six weeks of negotiations about a tie-up had ended in failure, raising questions about the future of the Frankfurt-based rivals.

(Writing by Arno Schuetze and John O'Donnell; Editing by Kirsten Donovan)

By Hans Seidenstuecker and Arno Schuetze