United States · Medicare Advantage · California

Which Medicare Advantage Plans Are Best in California for 2027?

By Best Worst Insurance Editorial TeamUpdated October 18, 2026

California is Kaiser Permanente's market. Of the 3,661,700 people in rated Medicare Advantage contracts there in October 2026, 1,386,181 are in Kaiser's H0524, rated 4.5 stars for 2027, and 73% of all members are in a contract with four stars or more ^[1,2,3]. The bad news is concentrated in two places. UnitedHealthcare of California, H0543, fell from 4 stars to 3 with 249,408 members in the state, and Blue Shield of California's H4937 fell a full star to 2.5, one of the lowest ratings of any sizeable plan in the country.

Best Worst Insurance Key Takeaways

73% of California's 3,661,700 Medicare Advantage members are in a four-star contract or better ^[1,2,3].
Kaiser Permanente H0524 (4.5 stars) has 1,386,181 members in California, more than a third of the market ^[1,2,3].
UnitedHealthcare H0543 fell from 4 to 3 stars with 249,408 California members ^[1,2,3].
Blue Shield of California H4937 fell from 3.5 to 2.5, with 40,105 members in the state ^[1,2,3].
The only five-star contract licensed in California is UnitedHealthcare H0710, which CMS flags as offering Special Needs Plans ^[1,4].

How we know: Members by state come from CMS's October 2026 enrollment by state, county and contract (the abridged file, which leaves out county rows of ten or fewer people); ratings are CMS's 2027 overall Star Ratings, published 8 October 2026. A contract's rating is national, so the stars here are the same as in any other state; what is California-specific is which contracts people here are in. These are 2026 contracts carrying their 2027 ratings, and what each sells in your county for 2027 is on Medicare Plan Finder. Tables come out of a committed script. Full methodology →

The fifteen Medicare Advantage contracts with the most members in California

Members in California only, October 2026, with each contract's 2027 rating ^[1,2,3].

Brand	Contract	2027 stars	Change from 2026	Members in California
Kaiser Permanente	H0524	4.5	no change	1,386,181
SCAN Health Plan	H5425	4	no change	407,947
UnitedHealthcare	H0543	3	4 → 3	249,408
Alignment Health Plan	H3815	3.5	4 → 3.5	225,326
Kaiser Permanente	H8794	4.5	4 → 4.5	145,925
UnitedHealthcare	H2001	4.5	no change	126,916
Humana	H5619	4	3 → 4	108,376
Anthem Blue Cross	H4471	3	no change	104,457
Anthem Blue Cross and Blue Shield	H4036	4.5	4 → 4.5	69,297
Blue Shield of California	H0504	4	no change	54,751
Astiva Health	H1993	4	no change	54,204
Clever Care Health Plan	H7607	4.5	4 → 4.5	53,392
Imperial Health Plan of California, Inc.	H5496	4	3.5 → 4	53,361
Anthem Blue Cross Partnership Plan	H4161	3	no change	51,509
Anthem Blue Cross	H0544	3.5	3 → 3.5	48,155

1. California's Medicare Advantage market

California is the largest Medicare Advantage state in our data and the most concentrated: the five largest contracts hold 66% of members ^[1,2,3]. Kaiser's H0524 alone holds more than a third. SCAN Health Plan's H5425, at 4 stars with 407,947 members, is second.

2. The best-rated options

Kaiser Permanente's H0524 and H8794, UnitedHealthcare's H2001, Anthem's H4036 and Clever Care's H7607 are rated 4.5 ^[1,2,3]. Kaiser is the obvious choice if you are happy to stay inside its system; if you are not, H2001 and H4036 are the 4.5-star alternatives with the most California members.

3. Who slipped

UnitedHealthcare's H0543 lost a full star, from 4 to 3, and has 249,408 members in California ^[1,2,3]. Alignment Health Plan's H3815 fell from 4 to 3.5. Blue Shield of California's H4937 fell from 3.5 to 2.5. Humana moved the other way, with H5619 rising from 3 to 4.

4. The weakest

Blue Shield's H4937 and Community Health Group's H4733, both at 2.5, are the lowest-rated contracts with more than 10,000 Californian members, and Anthem's H4471 and H4161 are at 3 ^[1,2,3]. Nationally: the worst Medicare Advantage plans.

Other states: Florida, Texas, Georgia, New York. All states compared: the state ranking.

Frequently asked questions

What is the best Medicare Advantage plan in California for 2027?

Kaiser Permanente's H0524 and H8794 and UnitedHealthcare's H2001 are rated 4.5 stars and are the best-rated contracts with large California enrollment ^[1,2,3]. Kaiser plans require you to use Kaiser's own doctors and hospitals.

Which California Medicare Advantage plans are rated worst?

Blue Shield of California H4937 and Community Health Group H4733 are at 2.5 stars, and UnitedHealthcare H0543 is at 3 with far more members ^[1,2,3].

Is there a 5-star Medicare Advantage plan in California?

One five-star contract, UnitedHealthcare H0710, is licensed in California for 2026, and CMS flags it as offering Special Needs Plans ^[1,4]. For most Californians the top rating available is 4.5.

Sources

Every figure on this page is footnoted to one of the primary documents below. Reliability tiers: A = regulator, court or filed document; B = reputable publisher or carrier official page; C = user-generated (reported by users).

1.Centers for Medicare & Medicaid Services — 2027 Part C and D Star Ratings data tables (Summary Ratings, Low Performing and High Performing Contracts, Domain and Measure Stars), 8 October 2026. https://www.cms.gov/files/zip/2027-star-ratings-data-tables-oct-8-2026.zipTier A · Regulator / court / filed document · Published 2026-10-08 · Accessed 2026-10-18
2.Centers for Medicare & Medicaid Services — 2026 Part C and D Star Ratings data tables, Summary Ratings as updated 22 July 2026. https://www.cms.gov/files/zip/2026-star-ratings-data-tables.zipTier A · Regulator / court / filed document · Published 2026-07-22 · Accessed 2026-10-18
3.Centers for Medicare & Medicaid Services — Monthly MA Enrollment by State/County/Contract, October 2026 (abridged version, rows of 10 or fewer enrollees excluded). https://www.cms.gov/files/zip/ma-enrollment-state-county-contract-october-2026-abridged-version-exclude-rows-10-or-less-enrollees.zipTier A · Regulator / court / filed document · Published 2026-10-15 · Accessed 2026-10-18
4.Centers for Medicare & Medicaid Services — MA and Part D State Service Area, October 2026. https://www.cms.gov/files/zip/state-service-area-october-2026.zipTier A · Regulator / court / filed document · Published 2026-10-15 · Accessed 2026-10-18