Final answer:
An insurer can exclude coverage for a preexisting condition on a Medicare Supplement Policy for up to 6 months, known as the preexisting condition waiting period.
Step-by-step explanation:
An insurer can exclude coverage for a preexisting condition on a Medicare Supplement Policy for up to 6 months. This time frame is known as the preexisting condition waiting period and is the standard maximum duration that Medicare Supplement or Medigap insurers are typically allowed to impose. However, if the individual had at least six months of continuous health insurance coverage prior to enrolling in a Medigap plan, and if the Medigap policy starts immediately after the previous coverage ends, this waiting period might be reduced or waived due to creditable coverage rules.