Citigroup Inc. agreed to sell its Yield Book and fixed income indexes to London Stock Exchange Group Plc in a $685 million cash deal, the latest in the U.S. banking giant's ongoing push to sell off noncore assets.

The Yield Book is Citi's fixed income analytics platform and serves approximately 350 institutions worldwide. In a May 30 press release, Citi said the sale was in line with its overall push to focus on core businesses and that it "[looks] forward to a long-term, productive partnership" with LSE.

Citi has pursued a strategy of selling off noncore assets for years, often in countries outside the U.S. The sale to LSE Group is one of more than 20 divestitures announced since 2015, according to an S&P Global Market Intelligence analysis.

Some of those divestitures were part of Citi Holdings, which consists of businesses and portfolios of assets that the company deemed not core to its franchise more than eight years ago. Citigroup has wound down the majority of Citi Holdings through a series of deals, portfolio sales, portfolio run-offs and repayments in recent years.

Given Citi's considerable size, some of those transactions were far larger than the sale of the Yield Book. Keefe Bruyette & Woods analyst Brian Kleinhanzl called the most recent deal a modest positive for Citi in that it will allow the bank to exit a noncore business and focus on improving returns. He expects the impact of the sale to be "immaterial" for Citi, but noted that if the company were to use all of the proceeds on an after-tax basis to buy back additional shares, his 2018 EPS estimate would increase by 2 cents "all else equal."

Kleinhanzl thinks this trend will continue. "We expect Citi and Universal Bank peers to continue to prune noncore businesses where management teams have determined that it makes more sense to divest versus invest," he wrote.