By Ross Kerber

BOSTON (Reuters) - A widening criminal probe casts new light on a bitter defeat hedge fund activist Bill Ackman suffered in his 2009 bid for board seats at U.S. retailer Target Corp.

Target for years has paid proxy solicitor Georgeson LLC to track the votes of its top investors. This week, five current and former Georgeson employees were charged with fraud for using bribes to get advance voting information on proxy battles.

The same tactics cited in the criminal complaint were used to help Target defeat Ackman in 2009, according to a former Georgeson employee turned whistleblower. Ackman, who runs hedge fund Pershing Square Capital Management, failed in the high-stakes battle to install his own slate of directors at Target and change its business direction.

"We knew long in advance who was winning" the Target proxy battle, Carl Clark, the whistleblower, told Reuters in an interview on Wednesday. He said he was fired by Georgeson in 2012 and that he flagged to authorities that bribes were being used to gain advance access on how investors were voting. The details were similar to those in the charges filed this week.

Georgeson has not been charged and said in a statement on Tuesday that it was cooperating with the investigation. A spokeswoman, Rachel Hamilton-Wilkes, declined to discuss details of the case.

Pershing Square executives declined to comment, spokesman Eric Kuo said.

A spokeswoman for the U.S. Justice Department, Christina DiIorio-Sterling, which filed the charges, declined to comment, citing the ongoing investigation.

Proxy solicitors like Georgeson have become more prominent with the rise of activist investors. They help companies assess whether shareholders will vote for or against management recommendations, including who should sit on the board.

Advance notice of likely proxy voting patterns would give Target extra time to identify holdouts and change investors' minds. Information filed in U.S. District Court in Boston by prosecutors suggests that Target and many other companies benefited from an inside line Georgeson had at Institutional Shareholder Services (ISS), which helps big investors cast their votes.

Target has not been accused of being aware of the behavior outlined in the criminal complaint. Target, which declined to comment, continued to use Georgeson for proxy solicitation services at least through this spring, according to disclosures with the U.S. Securities and Exchange Commission.

Brian Bennett, while working at ISS, tapped into the company's computer system to see how votes were being cast on behalf of big institutional investors that include mutual funds, according to U.S. prosecutors. They said he did this in exchange for tickets to sporting events provided by Georgeson employees. One bribe included two tickets worth more than $1,400 to a Boston Celtics basketball game, according to a criminal complaint.

Bennett pleaded guilty to fraud charges last year and awaits sentencing in U.S. District Court in Boston. His attorney on Friday declined to comment at a status conference held on his case.

Georgeson's Australian corporate parent, Computershare Ltd, hailed its work for Target in its 2009 annual report. "In one of the biggest proxy solicitations of the year, Georgeson represented Target Corporation in its successful proxy fight with a high profile activist investor."

Polling investors is hard work that involves a lot of cold calls to people who do not want to be harassed, according to this week's complaint. "(Eighty percent) of clients do not divulge," one of the former Georgeson employees, Michael Sedlak, told Bennett, according to the filing. "They just say they voted."

An attorney for Sedlak did not return messages seeking comment.

In 2013, Bennett's former company, ISS, paid $300,000 to settle SEC charges it failed to safeguard client voting data. The SEC said its investigation found that information on more than 100 shareholder advisory clients had been shared.

All of Target's four board nominees were re-elected with more than 70 percent of votes cast, while none of Ackman's nominees got more than 22 percent of votes cast, Target has said.

The case is unsettling, said one institutional investor who had backed one of Ackman's nominees in the 2009 vote, because companies already have a lot of influence over shareholder elections. In theory, inside information such as what the Georgeson team was getting could make a difference in close contests.

"It's a fairness issue," said the money manager, who was not authorized to speak publicly about the 2009 vote.