* Net profit down 34 pct at 1.1 billion euros
* Investment banking pretax profit down 22 percent
* Core tier one capital ratio 9.5 pct at end-March
* Says EU rules could mean 1.5-2 bln euro capital impact
* Says environment in investment banking challenging
* Shares rise 2.7 percent (Adds investor comment, updates shares)
By Thomas Atkins
FRANKFURT, April 29 (Reuters) - Deutsche Bank could turn to shareholders for cash to strengthen its capital base in the face of rising regulatory demands after first-quarter profits fell by more than a third.
The profit drop coupled with litigation costs, plus the impact of new European rules to bolster the region's banks have put pressure on Deutsche's capital, fuelling speculation that Germany's largest bank will need to raise equity before long.
"We would not rule out any option," the company's co-Chief Executive Anshu Jain said on a conference call on Tuesday with analysts following publication of first-quarter results.
Tapping existing shareholders for cash represents a clear change in Deutsche's plans after it said in January it had not discussed raising equity since getting 3 billion euros ($4.15 billion) from shareholders last year.
One of the bank's top 20 shareholders, who spoke on condition of anonymity, said the bank may need to raise as much as 10 billion euros in fresh equity.
But he urged the bank to wait until later in the year before returning cap-in-hand to shareholders so that it could offer more transparency and quantify its exact capital requirements.
"I'd welcome it if I could see what the clear need is," he said. "I think that at Deutsche Bank there is a capital hike of around 10 billion already priced in."
Deutsche Bank was not immediately available to respond.
Jon Peace, analyst at Nomura in London, said Deutsche Bank had clearly made an equity capital hike an available option and that investors expect an issue worth at least 3 billion euros.
"They're still toward the lower end of their peer group in terms of regulatory capital," he said.
Chief Financial Officer Stefan Krause said the bank preferred to retain earnings, sell non-essential assets and use other so-called organic measures to bolster capital first. But after that, the door was open to cutting banker bonuses and dividends and to raising fresh equity, he said.
Krause said bank health checks by European regulators had made it difficult to quantify capital needs.
The bank said it expected to face a hit of 1.5 to 2.0 billion euros due to new European Union regulations expected to come into force this year that impose prudent valuation rules on assets. That effect plus weaker results may complicate the bank's plans to raise capital through retained profit.
In the first quarter, pretax profit at Deutsche's investment bank, its biggest division, fell by more than a fifth, dragged down by a 16 percent year-on-year fall in trading revenue from fixed income, currencies and commodities.
Revenue declines in trading, especially in bonds, have already hit investment banking results at Barclays, JPMorgan and Citi.
Deutsche's net profit in the first quarter fell by 34 percent to 1.1 billion euros as an industry-wide slump in bond trading revenue depressed results.
The bank repeated its targets for 2015, which call for a post-tax return on equity (ROE) of over 12 percent for the group. The bank posted an ROE of 7.9 percent for the quarter.
Deutsche Bank had been expected to post quarterly net profit of 924 million euros, according to the average of a Reuters poll.
Shares in the bank rose 2.7 percent compared to a 1.9 percent gain in the STOXX Europe 600 bank index. Over the past 12 months, the shares have held mostly flat while the index has risen around 18 percent. ($1 = 0.7223 Euros) (Reporting by Thomas Atkins, Arno Schuetze, and Steve Slater; Editing by Jane Merriman)