When the details of Donald Trump's "One Big Beautiful Bill" were introduced, there was an unwelcome surprise for horseplayers as well as all gamblers. It included a provision whereby gamblers could only deduct 90% of their losses from their winnings. For example, if a gambler collected $100,000 in winning bets during a year while also losing $100,000, he or she would have to pay taxes on $10,000, even though no profit was actually made. The new law went into effect on Jan. 1. Unless something changes, when gamblers file their...