* Weimer, former Goldman Sachs partner, begins in January
* Deutsche Boerse seeks to move beyond insider trading probe
* Company can now function with "untainted leader" - investor (Adds details on Weimer, background, investor quote)
FRANKFURT, Nov 16 (Reuters) - Deutsche Boerse named Unicredit banker Theodor Weimer as its new CEO on Thursday as it attempts to move beyond an insider trading probe and a failed merger with the London stock exchange.
Weimer, who has headed Unicredit's Germany unit, will take the reins from Carsten Kengeter, who resigned from the German exchange operator amid the ongoing insider trading investigation. Kengeter has denied any wrongdoing.
The changing of the guard propels Weimer to the pinnacle of German finance and comes at a crucial moment for Deutsche Boerse. It hopes to position itself to profit from Britain's decision to leave the European Union by capturing a portion of the lucrative euro clearing market that is currently centered in London.
"We are relieved that an appropriate successor could be found quickly," said Ingo Speich, fund manager at Union Investment. "Most importantly, Deutsche Boerse can now fully focus on business as usual with an untainted leader."
Weimer, 57, will start his new job in January. He began his career in consulting for McKinsey and then Bain, before becoming an investment banker with Goldman Sachs where he was promoted to partner in 2004.
He joined Italian bank Unicredit in 2007, first as head of global investment banking and then as the head of German operations.
Weimer, an amateur pianist, fulfills many of the requirements that Joachim Faber, chairman of Deutsche Boerse's supervisory board, has said would be needed for the top job, including German as a native language, good political contacts and a strong knowledge of regulation.
At Unicredit, where he was responsible for nearly 14,000 staff, he was well respected. "He has the necessary grace for the job at Deutsche Boerse," said an employee representative on Unicredit's works council in Germany. "Our preference would be for him to stay."
Deutsche Boerse has said that it will shy away from big acquisitions.
Kengeter, just months into the job, designed a bold merger with the London Stock Exchange to create a global titan in the industry, but the merger plan eventually collapsed, costing shareholders tens of millions of euros in advisory and legal fees.
It also irked local politicians because Kengeter had agreed to the merged company's headquarters being in London, rather than Frankfurt, a decision then made more complicated by Britain's vote to leave the European Union.
The deal ensnared Kengeter in an insider trading scandal that cost him his job. He bought 4.5 million euros in shares two months before the announcement of formal merger talks, a boon to the share price that later aroused suspicions of insider trading.
Investigators raided his office and home on Feb. 1, and he has been under investigation ever since. All along, Kengeter and Deutsche Boerse have denied wrongdoing. Kengeter said he bought the shares through an official executive compensation program. (Reporting by Tom Sims and Andreas Framke; Additional reporting by Alexander Huebner; Editing by Arno Schuetze and Susan Fenton)