* In total, four new board members proposed
* All replace retiring board members
* Shareholders to vote on nominees in May
* Names announced amid leadership debate at lender (Adds investor quote, JPMorgan report, context on investment bank)
FRANKFURT, April 4 (Reuters) - Former Merrill Lynch CEO John Thain is being nominated to the supervisory board of Deutsche Bank, Germany's largest lender said on Wednesday.
The nominations for the supervisory board come amid questions over the leadership of the loss-making bank and the future direction of its investment banking division.
Deutsche Bank announced two other new nominees, Mayree Clark, founder and managing partner of Eachwin Capital, and Michele Trogni, previously group chief information officer at UBS.
A fourth proposed member of the board, Norbert Winkeljohann, chairman of the management board of PricewaterhouseCoopers Europe, had previously been announced.
The proposed board members replace four retiring members. Shareholders are due to vote on the nominees at the bank's annual general meeting next month.
Gerd Alexander Schuetz, who represents the interests of the Chinese conglomerate HNA, a major shareholder, is also up for re-election for a five-year term.
"We are delighted to have been able to attract such highly qualified new members, each with many years of experience in the financial sector," Deutsche Chairman Paul Achleitner said in a statement.
"They will ideally contribute to the wealth of skills that our Supervisory Board brings together," he said.
The lender is in the throes of a leadership debate. People familiar with the matter have told Reuters that Achleitner has started the search for a replacement for Chief Executive John Cryan. But Achleitner has come under criticism from major investors for the bank's woes and the CEO search.
Thain was named head of Merrill Lynch in 2007 but resigned from Bank of America Corp soon after it bought the brokerage at the height of the financial crisis. He also previously served as chief operating officer at Goldman Sachs Group Inc, where Achleitner also worked earlier in his career.
Thain, who began his banking career in 1979, formerly headed the New York Stock Exchange and engineered a series of mergers that shaped it into NYSE Euronext by 2007.
Thain was appointed a director of Uber Technologies last year.
"The nomination of Thain underscores that investment banking, especially investment banking in the U.S., will remain core to the bank's strategy," said Ingo Speich, a fund manager at Union Investment, which holds Deutsche stock.
Deutsche Bank is conducting a global review of its investment bank, known internally as Project Colombo. It could result in the exit from or strengthening of certain activities.
JP Morgan weighed in on that debate on Wednesday with the publication of a research report for clients that said Deutsche should shrink its U.S. business to create shareholder value. (Reporting by Tom Sims and Hans Seidenstuecker Editing by Edward Taylor and Adrian Croft)