In baseball, going halfsies is a really controversial idea.A formal revenue split between players and owners is a key feature of a salary-cap system, which Major League Baseball’s owners want to introduce.“Our salary cap and floor proposal levels the playing field while sharing baseball revenue with the players 50-50, which means players and clubs would share equally as revenue grows,” said Glen Caplin, an MLB spokesperson, in a statement to The Athletic.The players’ union has a long list of reasons it’s opposed to MLB’s cap setup. Among them: Players already receive “well over” half the industry’s annual $12 billion haul. But the union also thinks the league is wrong to paint its proposal as even-steven.“It’s no surprise that MLB would resort to deception in framing their salary cap proposals as ‘sharing equally,’” Bruce Meyer, the interim head of the Players Association, said in his own statement. “MLB hasn’t proposed a 50-50 ‘split’ of revenues. Any suggestion otherwise is misleading propaganda.”When it comes to the revenue divide in a cap system, there’s crucial information to understand beyond just the percentage — namely, the denominator. What would be included, and what would be taken off the top, from the pot of money the sides would share?The answer is laid out in a lengthy proposal MLB made on May 28, which was reviewed by The Athletic and includes a calculation MLB is dubbing just “baseball revenue,” or BR.It has no shortage of deductions.MLB could take up to 17 percent of local revenues off the top annually as expenses, plus up to 22 percent of national revenues. Plus, some areas would have no expense cap, such as construction and renovation costs for ballparks, including spring-training facilities.The league-run TV station MLB Network would have no deduction limit, and for 2027 and 2028, neither would costs from any team’s local broadcasts.The league also wants unlimited deductions for what it broadly termed “new ventures.”“MLB’s so-called revenue ‘split’ is calculated only after skimming billions off the top in supposed expenses and exclusions,” Meyer continued in his statement. “There is also no ‘sharing equally’ in franchise value growth, expansion fees, or the vast amounts of revenues being generated around ballparks across the league.”While it might come as a surprise, the revenue split is probably the most important piece of a cap system — even more so than the upper and lower limits on salary each team would have to respect. The split is the real salary cap.That’s because after each season, player salaries would be adjusted to make sure players and owners alike get their designated percentage of revenue. For this reason, the league wants players to put up to 10 percent of their salaries into escrow each year.These accounting gymnastics may sound familiar to those who follow other sports.In the National Basketball Association, the pool of money that’s doled out is known as basketball-related income, or BRI. In the National Hockey League, the tabulation is called hockey-related revenue, or HRR.“The proposed definition of baseball revenue aligns closely with the proven approaches used in other leagues,” Caplin said. “MLB player compensation has grown more slowly than player compensation in the other leagues.”All the other leagues indeed permit deductions, but the NFL has notably fewer compared to the NBA and NHL, and to MLB’s desired setup.None of the other cap leagues share the proceeds of franchise sales with players, either. Despite this, the revenue split in the NHL is still regularly discussed as “50-50.”