The out-of-pocket maximum built into Original Medicare, zero, meaning there isn’t one. Every other major form of insurance in American life, from an employer health plan to a Marketplace policy to Medicare Advantage itself, comes with a ceiling on what a person pays in a bad year. Original Medicare, the program most Americans default into at 65, does not. Agents who spend their careers fielding this exact question, gathered on Medicare Agents Hub’s nationwide platform, describe it as one of the most consequential gaps in the entire system, and the one new retirees are least likely to know about until they need it.
The mechanics are simple enough to explain in a sentence, and expensive enough to reshape a retirement. Medicare Part B pays 80% of approved outpatient costs. The beneficiary owes the other 20%. There is no annual cap on that 20% — not $5,000, not $10,000, nothing.
What 20% actually means in dollars
Agents who answer this question tend to reach for the same tool: arithmetic. Karen Ansell, an agent licensed in Florida, Georgia, Kentucky and Ohio, walked through the numbers on a hospital admission: a $1,676 Part A deductible per benefit period, then $419 a day from day 61 to 90, then $838 a day after that, with 20% Part B coinsurance stacked on top and no ceiling on any of it.
Morgan Greer, licensed in Kansas and Missouri, ran the math on a cancer diagnosis. “Let’s take a cancer diagnosis with 6 months of chemo,” Greer said. “There could easily be $1M or more in Part B costs, which means you are paying $200,000! This is how medical debt happens.” Clarence “Mark” Christiansen, licensed in Wisconsin and 17 other states, arrived at a similar figure independently: “People who need $1 million worth of outpatient services such as chemotherapy will be looking at a bill in the neighborhood of $200,000.”
Ron Ray, a Texas broker, offered a real hospital bill instead of a hypothetical one. “If you had a surgery and hospital stay that costs $500,000, Medicare will only pay about $400,000 and you are responsible for the rest, or $100,000,” Ray said. “This could have an adverse effect on your retirement plan.”
Why healthy people fall into the gap
The agents describe a consistent pattern: the people most at risk are the ones who feel the least urgency. A 66-year-old who rarely sees a doctor has no reason to notice that Original Medicare alone leaves them exposed, until a diagnosis changes the picture with no warning.
Shauneen Sullivan, licensed across Florida, Arizona, Georgia and nine other states, put it directly: “Sticking with Original Medicare without a Medigap plan may seem fine if you’re healthy now, but it comes with significant financial risk if your health changes unexpectedly.” She added a detail agents raise often — the coverage decision made at 65 doesn’t stay open forever. “If you decide to get a Medigap plan later, you may face medical underwriting, higher premiums, or even be denied coverage, depending on your health and state rules.”
Dutch VanHoesen, a Florida broker, described a client who tried to save money by skipping Medigap for a cheaper Medicare Advantage plan, then developed a condition requiring quarterly eye injections for the rest of her life. “This cost is reaching her out of pocket maximum of $5,500 which is more than twice the annual cost of her supplement,” VanHoesen said. “In this particular case it would have been more cost effective for her to have been on the Medigap plan costing her $2,400 per year.” The plan that looked cheaper on paper turned out to cost more once she actually used it.
Stephen Merrill, a California agent, called the exposure by its plainest name. “MEDICAL BANKRUPTCY,” Merrill said. “You might be exposing your savings to unlimited risk. There’s no stop-loss on out-of-pocket costs.”
The two ways agents say to close the gap
The fix agents describe isn’t complicated, even if the math behind it is sobering. A Medigap policy (also called Medicare Supplement insurance) picks up some or all of that uncapped 20%, in exchange for a monthly premium that, unlike the coinsurance it replaces, has a knowable ceiling. Kim Mitchell-Hargis, a broker licensed in Tennessee, Florida and Kentucky, estimated that her clients pay $450 to $500 a month on average for the combination of Medigap and Part D drug coverage. Not cheap, but calculable in a way the alternative isn’t. “The Medigap plan will benefit you and keep you from going bankrupt,” she said.
The other route several agents pointed to is Medicare Advantage, which by law caps annual out-of-pocket spending (typically in the $4,000 to $9,000 range, depending on the plan) in exchange for a defined network of doctors and hospitals. Lauren Fodde, a broker licensed in Missouri and Florida, framed the tradeoff plainly: “Original Medicare + Medigap = highest protection, more freedom, higher premium. Medicare Advantage = cost limits and extras, but provider restrictions. Original Medicare alone = highest financial risk.”
What nearly none of the agents recommend is the third option, enrolling in Part B and stopping there. Nick Mangini, a broker licensed in Florida and 32 other states, put the warning in the plainest terms of all: “You are responsible for the remaining 20% coinsurance FOREVER and there is NO MAXIMUM! This means you will ALWAYS PAY the 20% FOREVER!” It’s not a subtle point, and agents who deal with the aftermath of skipping that decision don’t make it subtly.
