By Olivia Oran

NEW YORK (Reuters) - Credit Suisse Group AG <CSGN.S> is accusing a group of five investment bankers who left for Jefferies Group LLC in May of stealing confidential information and trying to coax former colleagues to join them.

The dispute, which has not been previously reported, offers insight into how the Swiss bank's push into wealth management under Chief Executive Officer Tidjane Thiam may be prompting the departure of bankers that Wall Street businesses want to retain.

Credit Suisse said in a petition in New York State Supreme Court in June that the bankers printed out and had access to proprietary information that could be used for the benefit of Jefferies. Documents in the court case also accused the bankers of conspiring to attract members of Credit Suisse's technology banking team to Jefferies.

The Swiss bank is asking the court to block the five, all former managing directors, from using proprietary information it said they obtained before quitting. Credit Suisse did not name Jefferies Group as a defendant in the case.

The former employees, Steve West, Bill Brady, John Metz, Cameron Lester and Cully Davis, had worked in Credit Suisse's technology, media and telecom investment banking group, handling high-profile deals such as Alibaba Group Holding Ltd's <BABA.N> $25 billion IPO. They denied Credit Suisse's allegations.

Lawyers for the bankers and Jefferies could not immediately be reached to comment. Credit Suisse declined to comment.

The departure of the five to Jefferies raised eyebrows on Wall Street. Several of them had worked at Credit Suisse for over a decade. But in court filings, their lawyers argued they had little choice but to leave Credit Suisse to foster their careers, since the Swiss bank was moving away from "investment banking."

The lawyers cited news articles with headlines to that effect and comments from Thiam, who became CEO in June 2015, about the bank's shift toward wealth management and away from capital-intensive businesses such as bond trading.

While the term "investment banking" is sometimes used to refer broadly to institutional businesses, Credit Suisse has said it is not moving away from traditional work done by these former employees, like advising on mergers or underwriting initial public offerings.

Nonetheless, Thiam's emphasis of wealth management has alienated some of the dealmakers.

Credit Suisse has suffered a number of senior banker departures in 2016, including global chairman of M&A David DeNunzio, who left for a role at Wells Fargo & Co <WFC.N>. For the first half of 2016, Credit Suisse ranked No. 6 for U.S. announced M&A, down from No. 4 during the same period a year earlier, according to Thomson Reuters data.

In court documents, Credit Suisse said its former employees printed and transferred confidential information about transactions, client presentations, conferences and internal research. The bank said they could cause "irreparable harm" if they used the information. They said the information could help the five to pursue deals that were in Credit Suisse's pipeline.

David Wah, global co-head of the tech, media and telecom group at Credit Suisse, said in an affidavit that senior managers at Jefferies were also soliciting junior Credit Suisse employees.

Wah called the recruitment efforts "ongoing and aggressive" and targeted in such a way that made Credit Suisse suspect the former bankers. Under separation agreements, the five were prohibited from recruiting from Credit Suisse for three months.

In court filings, lawyers for the former employees denied they had taken confidential information or courted other Credit Suisse employees, and said the Swiss bank was retaliating against them for leaving.

"After publicly announcing that it would shift focus from investment banking and reduce resources allocated thereto, Credit Suisse is now indignant that respondents found another opportunity to attempt to move on with their career," the bankers' lawyers wrote.

The filings also revealed retention agreements Credit Suisse had given some of the bankers in 2015 and 2016 to discourage them from leaving. These cash awards, which vested at the end of each year, were on top of their annual salaries and end-of-year bonuses.

Such retention agreements are rare, compensation experts said, because they are all in cash. Bank compensation is typically tied up in stock to encourage long-term performance, with a small portion payable in up-front cash.

The case is Credit Suisse Securities USA LLC v. Stephen West, William Brady, John Metz, Robert Lester and Charles Davis, Supreme Court, New York of New York, No. 653002/2016