Reference · 2026 · Updated August 2026

Medicare & Insurance-Agent Glossary

Every term that quietly trips people up — defined in one plain-English sentence. Current for 2026.

AEP (Annual Enrollment Period)
The yearly window, October 15 to December 7, when anyone with Medicare can join, switch, or drop a Medicare Advantage or Part D drug plan. Changes take effect January 1.
OEP (Medicare Advantage Open Enrollment)
January 1 to March 31. People already in a Medicare Advantage plan can switch to another MA plan or return to Original Medicare once during this window.
IEP (Initial Enrollment Period)
The 7-month window around your 65th birthday — the three months before, your birthday month, and the three months after — when you first sign up for Medicare.
SEP (Special Enrollment Period)
A window outside the normal periods, triggered by a life event such as moving, losing employer coverage, or a plan leaving your area, that lets you change Medicare coverage.
IRMAA (Income-Related Monthly Adjustment Amount)
An income-based surcharge added to Medicare Part B and Part D premiums for higher earners. It is based on your MAGI from two years prior. (See the IRMAA Calculator for current-year brackets.)
MAGI (Modified Adjusted Gross Income)
Your adjusted gross income plus tax-exempt interest. Medicare uses your MAGI from two years ago to decide whether you owe the IRMAA surcharge.
Part A
The hospital-insurance part of Medicare. It covers inpatient hospital stays, skilled nursing, hospice, and some home health care. Most people pay no premium for Part A.
Part B
The medical-insurance part of Medicare. It covers doctor visits, outpatient care, preventive services, and durable medical equipment, for a monthly premium.
Part C (Medicare Advantage)
An all-in-one alternative to Original Medicare offered by private insurers. It bundles Part A and Part B, usually adds Part D drug coverage, and often includes extras like dental or vision.
Part D
Medicare's prescription-drug coverage, sold by private plans. It can be a standalone plan added to Original Medicare or built into a Medicare Advantage plan.
Medigap (Medicare Supplement)
Private insurance that pays some of the out-of-pocket costs Original Medicare leaves behind, such as copays, coinsurance, and deductibles. It does not work with Medicare Advantage.
MOOP (Maximum Out-of-Pocket)
The yearly cap on what a Medicare Advantage member pays for covered medical services. Once they hit it, the plan pays 100% of covered care for the rest of the year.
Coverage Gap (Donut Hole)
A former phase of Part D where members paid more once drug spending hit a threshold. Starting in 2025 it was replaced by a hard annual out-of-pocket cap on Part D drug costs.
LEP (Late Enrollment Penalty)
A permanent surcharge added to your Part B or Part D premium if you go without creditable coverage after you were first eligible. (See the Penalty Calculator.)
LIS / Extra Help
A federal program that lowers Part D drug costs — premiums, deductibles, and copays — for people with limited income and resources.
MSP (Medicare Savings Program)
State programs that help pay Medicare premiums, and sometimes deductibles and coinsurance, for people with limited income.
Star Ratings
CMS's 1-to-5 quality scores for Medicare Advantage and Part D plans, based on member experience, outcomes, and service. Higher-rated plans can market year-round.
Guaranteed Issue
Times when an insurer must sell you a Medigap policy without medical underwriting and cannot charge more for health history — for example, when you lose other coverage.
SOA (Scope of Appointment)
A CMS-required form documenting which product types a beneficiary agreed to discuss before a sales appointment. Under the CY2027 final rule (91 FR 17384), it must be agreed before the appointment begins — the prior 48-hour advance requirement is eliminated effective October 1, 2026 (it still applies through September 30, 2026).
CTM (Complaint Tracking Module)
The CMS system where Medicare complaints against agents and plans are logged. A pattern of CTMs can trigger oversight, so agents keep clean documentation.
Chargeback
When an insurer reclaims commission already paid because a policy lapses, is canceled, or the member disenrolls inside the early-months window. Common in Medicare and final expense.
Persistency
The percentage of an agent's policies that stay in force over time. Carriers watch persistency closely; low persistency can cost an agent their contract.
TCPA (Telephone Consumer Protection Act)
The federal law governing telemarketing calls and texts. Agents must have documented consent to contact leads and honor do-not-call requests, or risk steep per-contact penalties.
Original Medicare
The traditional fee-for-service program run by the federal government — Part A plus Part B. Members can see any provider that accepts Medicare and may add Medigap and Part D.
ANOC (Annual Notice of Change)
The document a Medicare Advantage or Part D plan mails each fall showing what's changing — premium, copays, drugs, network — for the coming year. The trigger for the annual plan review.
Formulary
A plan's list of covered prescription drugs, organized into cost tiers. A drug's tier and rules (like prior authorization) determine what the member pays.
Prior Authorization
A plan requirement that a provider get approval before a service or drug is covered. A common reason a claim is delayed or denied.
Network (HMO / PPO)
The doctors and hospitals a Medicare Advantage plan contracts with. HMOs generally require in-network care and referrals; PPOs allow out-of-network care at higher cost.
Creditable Coverage
Drug coverage at least as good as Medicare Part D. Keeping creditable coverage avoids the Part D late-enrollment penalty.
Ready-to-Sell (RTS)
The status an agent reaches for a given carrier after completing AHIP plus that carrier's annual certification and contracting. An agent cannot sell a plan until RTS for it.
AHIP
America's Health Insurance Plans certification — the annual training and test most carriers require before an agent can sell Medicare Advantage or Part D plans for the year.
FMO / IMO
Field/Independent Marketing Organization — the upline that contracts agents with carriers and provides support, leads, and tools. Agents write business 'through' an FMO.
AOR (Agent of Record)
The agent officially credited with a policy, and who receives its commission. AOR changes are tightly controlled by CMS rules.
Rapid Disenrollment
When a member leaves a plan within roughly the first three months. It usually triggers a full commission chargeback to the agent.
E&O Insurance
Errors & Omissions insurance — professional liability coverage most carriers require an agent to carry before contracting.
Effectuation
The point at which an enrollment is accepted and the policy becomes active. Commission is typically paid after a policy effectuates.
T65 (Turning 65)
Consumers approaching age 65 and their Initial Enrollment Period — the highest-value prospects for a Medicare agent.
Book of Business
The full set of clients and active policies an agent has written. Retaining the book (high persistency) is where long-term renewal income comes from.

👔 Are you a Medicare agent?

These free tools handle one client at a time. Our Excel + Google Sheets toolkits run your whole book — client CRM, 60-day renewal radar, IRMAA appeals, commission & chargeback tracking, and compliance logs. Built for agents, instant download, no monthly fee.

New here? Start for $7.49 →

…or browse all the agent toolkits on Etsy →

Related free tools

2026 IRMAA Calculator
Enter income → your exact Part B & D surcharge.
Enrollment Period Finder
Find the exact window you can change plans.
Late Enrollment Penalty
Estimate the permanent Part B / D penalty.