Bank of America is overhauling one of its most high-profile and lucrative businesses, its $8.4 billion fixed-income trading division.The bank is forming two new units and appointing new leadership.As part of the changes, Frank Kotsen, global head of credit trading and a 23-year company veteran, is departing the firm.The bank's credit-trading division is one of the best on Wall Street, routinely a top-3 contender.Click here for more BI Prime storiesA large reorg is underway in one of Bank of America's most high-profile and lucrative businesses, its $8.4 billion fixed-income trading division, including senior leadership changes and two new units formed out of the combination of existing trading desks.The bank is retooling its credit trading operation, combining the firm's global developed and emerging credit trading franchises, according to an internal memo viewed by Business Insider.Frank Kotsen, global head of credit and special situations and a 23-year company lifer, has decided to leave the firm, according to the memo.With Kotsen departing, Brian Carosielli, global head of mortgages and securitized products trading, and Brian Weinstein, global cohead of emerging markets trading, have been promoted and will jointly run the new Global Credit group, according to the memo from FICC trading coheads Jim Demare and Bernie Mensah.Kotsen, who joined the firm as a summer associate in 1995 and has steadily ascended the firm's ranks, has managed the firm's massive credit-trading group since 2014. Before that he ran special situations and loan trading from 2009 until 2014.The firm is also changing up its foreign exchange trading business, combing G10 Trading and Emerging Markets Local Currency Trading. Denis Manelski, a 15-year company veteran, will lead the combined group, according to the memo."As we start the new decade, we continue to focus on the best way to serve our clients and stay ahead of significant changes taking place in technology and other factors impacting our business and the markets," the memo from DeMare and Mensah reads.A Bank of America spokesman declined to comment on the changes but confirmed the contents of the memo.Other changes outlined in the memo:Matt McQueen, global head of mortgages trading, will replace Carosielli as global head of mortgages and securitized products trading.Mark Davies will cohead Global Markets Data and Innovation with Brice Rosenzweig. Davies, will also head Global Markets Data Management, "which includes realigning the Global Markets Data Strategy and Remediation Group under his leadership. In this capacity, he will lead the effort to drive our overall data management strategy."The firm's fixed-income, currencies, and commodities (FICC) division is a perennial top-3 performer on Wall Street, and it's credit operation is especially strong.Bank of America's FICC sales and trading operations contributed $8.4 billion in revenues in 2019, 54% of the firm's global markets haul for the year.On Wednesday the bank reported a 25% improvement in FICC trading revenues in the fourth quarter, amid a wave of strong bond-trading results by Wall Street banks.However, the division's 2019 results, essentially flat with 2018, weren't as strong as competitors. Other top banks, including JPMorgan, Citi, and Morgan Stanley, saw substantial full-year gains in FICC trading.Check out the org chart for the 30 most powerful people in Bank of America's bond-trading division. Join the conversation about this storyNOW WATCH: WeWork went from a $47 billion valuation to a failed IPO. Here's how the company makes money. Click here to read full news..