After decades of selling insurance, Illinois-based broker John Jaggi had never seen anything like it. More than 80 of his customers who were enrolled in the same Medicare supplemental plan from the insurer Chubb got hit last August with a 45% increase. “In my 49 years of doing biz as a broker, I’ve never seen a premium increase be effective immediately on everyone, instead of on their policy anniversary,” said Jaggi, whose brokerage scrambled to find more affordable options for clients. The policies pick up deductibles and other costs not covered in traditional Medicare, and without one there is no upper limit on how much a consumer might owe each year. While 45% was an unusually big jump, Jaggi and other brokers say double-digit premium increases for Medicare supplemental, or Medigap, policies are becoming the norm. A Chubb spokesperson did not respond to requests for comment on the increase. More than 12 million people — about 43% of those in traditional Medicare — buy a Medigap policy.…