Networks
HMO, PPO, EPO and POS — without the stereotypes
Network type describes how a plan organizes provider access and cost sharing. It does not tell you by itself whether a plan is cheap, good or right for your doctors.
Reviewed November 2026
HealthCare.gov's basic plan-type definitions
| Type | Network rule in plain language | What to verify |
|---|---|---|
| EPO | Generally network-only except emergencies | Check the plan rather than assuming referral rules |
| HMO | Usually limits coverage to contracted providers except emergencies | Service area, primary care and referrals can matter |
| POS | Lower cost in-network; referral required for specialists under HealthCare.gov's definition | Out-of-network rules and cost sharing vary |
| PPO | Lower cost in-network; out-of-network available without referral for additional cost | Out-of-network bills can be substantially different |
These are general Marketplace definitions. Employer and other coverage can have different documents and rules, so use the plan's own materials as the final source.
The two-list check
Providers and prescriptions
Provider directory
- Search the exact doctor, facility and location.
- Call the office with the full plan and network name.
- Ask about referrals and scheduled appointments.
- Recheck before a plan switch or major procedure.
Formulary
- Find the exact medication and dosage form.
- Check the tier and expected cost sharing.
- Look for authorization, quantity or pharmacy rules.
- Ask the plan or clinician about covered alternatives if needed.
If treatment is already underway
Do not leave ongoing care for the last day
Before changing plans, ask how scheduled appointments, ongoing treatment, referrals and prescriptions will be handled on the new effective date. Some plans have transition-of-care processes, but they are not something to assume. Get instructions from the new plan in writing where possible.
Common questions
Does PPO mean every doctor is covered?+
No. A PPO can offer out-of-network coverage at additional cost, but allowed charges, deductibles and balance billing can differ. Verify the provider and the plan rules.
Do all HMOs require referrals?+
Not every plan works identically. HealthCare.gov describes general types, but your plan documents determine referral requirements.
Is an online provider directory always current?+
Directories can change or contain outdated information. Use the directory and confirm with the provider's office and plan when network status is important.
Are emergency services handled like routine out-of-network care?+
Emergency rules have special considerations and should not be inferred from a simple network chart. Review the plan's emergency and stabilization provisions.