R.J. O’Brien Associates, a family-owned firm intertwined with Chicago’s legacy in the global market for futures trading, said Monday it’s being acquired by a New York-based company in a cash and stock deal worth $900 million.StoneX Group, a Fortune 100 financial services provider, said it exp ects the sale will close in the last half of 2025, pending regulatory review. StoneX will absorb the O’Brien firm’s 75,000 client accounts into its own network of around 450,000 customers.The Chicago company, known as RJO for short, ranks as the oldest independent futures brokerage in the U.S. It's the last founding member of the Chicago Mercantile Exchange to survive today.RJO can be traced back to 1914, the early agricultural days of trading here, when founder John V. McCarthy used a pushcart to sell butter and eggs. In 1919, he and others founded the Merc when it grew out of the old Chicago Butter and Egg Board. Robert O’Brien Sr. (second from left) celebrates the start of trading in live hog futures at the Chicago Mercantile Exchange in 1966. He was then president of the forerunner of R.J. O’Brien Associates and later would become chairman of the Merc.R.J. O’Brien Associates He had a daughter that married into the O’Brien family and a business dynasty developed over the years. The company expanded its trading lines, joined the Chicago Board of Trade and opened offices overseas, becoming a force in all futures markets. Today, the Merc and the Board of Trade operate under a single corporation.Sean O’Connor, executive vice chairman of StoneX, said the “transformational” sale will make his company a leader in trading of derivatives, the broad name for options and futures contracts.Gerald Corcoran, RJO chairman and CEO, said in a news release, “We’re extraordinarily excited about this partnership between two great companies that each bring over a century of history in the futures industry and complementary capabilities, products, services, and cultures. We both prioritize a profound commitment to our clients and a focus on prudent risk management.”Corcoran will continue with StoneX in a “senior leadership role,” the companies said.The R.J. O’Brien name will be kept “for a period of time to be determined,” an RJO spokesperson said. It’s not known if the sale will lead to layoffs, but StoneX estimates it will yield about $50 million in savings, mostly by trimming redundant back office functions.RJO said it has 590 employees, including 300 in Chicago. “Chicago will absolutely remain an important part of the fabric of the combined company,” the spokesperson said.While RJO is mostly held by the O’Brien family, ownership has gone through changes in recent years. John O’Brien Sr. and his father, Robert O’Brien Sr., both died in 2022. They were a grandson and son-in-law, respectively, of McCarthy.StoneX has about 4,400 employees. It said RJO in 2024 had $766 million in revenue and $170 million in earnings before interest, taxes, depreciation and amortization.It said it will issue debt to finance the $625 million cash portion of the purchase. The balance will come from issuing about 3.5 million shares of StoneX stock, which ended Monday’s trading at $79.10 a share. The buyer assumes $143 million of RJO debt.“So many of our family members have been privileged to lead the company and provide guidance and counsel. We feel so close to our clients, brokers and employees; they’re extended family to us,” RJO board member Bob O’Brien Jr. said in a news release. “This merger is the natural next step in the history of the company, and the O’Brien family is enthusiastic about playing a new role as major shareholders in another great company that will build on that legacy.” ...read more read less