Citigroup's ( C) chief economist Lewis Alexander is leaving the company for a job at the Treasury Department, an Citigroup memo says, the Wall Street Journal reports. Alexander, who has been at Citigroup since 1999 and before that worked at the Federal Reserve, will head to the Treasury "to work on domestic financial issues," said the Citigroup memo, which was sent Tuesday. The economist will serve as a counselor to Treasury Secretary Timothy Geithner, a government official said. Alexander and a Treasury spokesman weren't available to comment Tuesday. A Citigroup spokesman declined to elaborate on the company's memo, according to the Journal. Alexander is joining the Treasury Department at a time when the department is struggling in its efforts to battle the financial crisis. Geithner so far has battled the crisis with no key deputies in place. That's made for a rocky start for the man President Barack Obama put on the front lines of the financial crisis. Treasury's handling of a $700 billion financial bailout fund has drawn fierce criticism from Congress and the American public. The government has put up hundreds of billions of taxpayers' dollars to rescue troubled financial companies, including American International Group ( AIG), Bank of America ( BAC) and Alexander's own Citigroup. As a Wall Street insider from a bank that has been one of the largest recipients of government rescue funds, Alexander's appointment could raise some eyebrows.