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Medicare Advantage Enrollment Tracker · Montana

Medicare Advantage Enrollment in Montana

Montana had 80,776 Medicare Advantage members in September 2026, by the CMS county file, which includes employer group plans. That is up 1.0% from Sep 2025, slower than the national 2.0%. Montana ranks 45th by members and holds 0.2% of the national total.

Humana leads with 69.4% of members who have a carrier label (contract file, September 2026). Among individual plans, which leave out employer group coverage, enrollment is up 2.4% in the 12 months to September 2026.

By Senior Deal Club Standards Desk · Data as of September 2026 · Editorial policy

Data as ofCMS public files, monthly snapshot

  • These totals include employer and union group plans.
    Why this matters

    The CMS contract and county files count group plans that retirees get through a former employer. They are not plans you can pick on your own. Counts here are larger than the individual-plan counts on county pages.

  • Some months are missing from the source.
    Why this matters

    CMS did not publish every month. Lines break at a missing month instead of guessing a value. A dotted line, where shown, only joins the two sides.

Montana at a glance

Medicare Advantage members

80,776

Montana members by month: from 67K in Jan 2023 to 80.8K in Sep 2026

County file · Sep 2026. Includes employer group plans. Rank: 45.

County file · Sep 2026
CMS state, county and plan-type file (SCP). The same plans split by state and county, with employer and union group plans included. CMS hides counts of 10 or fewer.

12-month change

+1.0%

up 1.0 percent vs Sep 2025

County file · Sep 2026. National: +2.0%.

Share of national total

0.2%

County file · Sep 2026. Of jurisdictions that report every month.

Individual plan members

73,154

Individual MA · Sep 2026. Employer group plans left out.

Individual MA · Sep 2026
Individual Medicare Advantage plans (IND), from county data. Employer and union group plans are left out, so counts are smaller than in the other two files.

Largest carrier

Humana

69.4% of members with a carrier label. Contract file · Sep 2026.

Montana members by month

Medicare Advantage members in Montana

Members, by month.

County file · Sep 2026
CMS state, county and plan-type file (SCP). The same plans split by state and county, with employer and union group plans included. CMS hides counts of 10 or fewer.
Medicare Advantage members in MontanaLine chart, January 2023 to September 2026. Montana: 80.8K in September 2026. Shaded bands mark months with no data.65K70K75K80K85K2023202420252026Montana80.8K
Medicare Advantage members in MontanaLine chart, January 2023 to September 2026. Montana: 80.8K in September 2026. Shaded bands mark months with no data.65K70K75K80K85K20232025Montana80.8K
  • Montana
  • Shaded: no data that month
View the data table
Medicare Advantage members in Montana: values by month
MonthMontana
Sep 202680.8K
Aug 202680.8K
Jul 202680.8K
Jun 202680.8K
May 202680.6K
Apr 202680.5K
Mar 202680.2K
Feb 202680K
Jan 202678.3K
Dec 202580.1K
Nov 202580.1K
Oct 202580.1K
Sep 202579.9K
Aug 202579.9K
Jul 202579.7K
Jun 202579.5K
May 202579.4K
Apr 202579.4K
Mar 202579.2K
Feb 202578.9K
Jan 202577.4K
Dec 202477.2K
Nov 202477.2K
Oct 202477.2K
Sep 202476.9K
Aug 202477K
Jul 202476.8K
Jun 202476.7K
May 202476.4K
Apr 202476.2K
Mar 202476K
Feb 202475.7K
Jan 202474.9K
Dec 2023–
Nov 202370.7K
Oct 202370.5K
Sep 202370.3K
Aug 202370.1K
Jul 2023–
Jun 202369.6K
May 202369.4K
Apr 202369.2K
Mar 202369K
Feb 202368.8K
Jan 202367K

County file · Sep 2026. Employer group plans included.

Montana and the nation, Jan 2023 = 100

Each line is members divided by members in the start month, times 100.

County file · Sep 2026
CMS state, county and plan-type file (SCP). The same plans split by state and county, with employer and union group plans included. CMS hides counts of 10 or fewer.
Montana and the nation, Jan 2023 = 100Line chart, January 2023 to September 2026. Montana: 120.6 in September 2026. National (same jurisdictions each month): 117.8 in September 2026. Shaded bands mark months with no data.1001101201302023202420252026Montana120.6National117.8
Montana and the nation, Jan 2023 = 100Line chart, January 2023 to September 2026. Montana: 120.6 in September 2026. National (same jurisdictions each month): 117.8 in September 2026. Shaded bands mark months with no data.10011012013020232025Montana120.6National117.8
  • Montana
  • National (same jurisdictions each month)
  • Shaded: no data that month
View the data table
Montana and the nation, Jan 2023 = 100: values by month
MonthMontanaNational (same jurisdictions each month)
Sep 2026120.6117.8
Aug 2026120.6117.8
Jul 2026120.6117.5
Jun 2026120.6117.4
May 2026120.4117.2
Apr 2026120.2116.9
Mar 2026119.8116.7
Feb 2026119.4116.3
Jan 2026116.9114.7
Dec 2025119.6115.9
Nov 2025119.6115.9
Oct 2025119.5115.7
Sep 2025119.3115.5
Aug 2025119.2115.3
Jul 2025118.9115
Jun 2025118.8114.8
May 2025118.5114.4
Apr 2025118.5114.2
Mar 2025118.3113.8
Feb 2025117.8113.4
Jan 2025115.6111.9
Dec 2024115.3112
Nov 2024115.2112
Oct 2024115.2111.7
Sep 2024114.8111.5
Aug 2024114.9111.2
Jul 2024114.7110.9
Jun 2024114.6110.7
May 2024114.1110.5
Apr 2024113.7110
Mar 2024113.4109.7
Feb 2024113109.3
Jan 2024111.8108.7
Dec 2023––
Nov 2023105.6105.9
Oct 2023105.2105.6
Sep 2023104.9105.2
Aug 2023104.7104.9
Jul 2023––
Jun 2023103.8104.1
May 2023103.7103.8
Apr 2023103.3103.4
Mar 2023103.1103
Feb 2023102.7102.2
Jan 2023100100

County file · Sep 2026. National line sums the jurisdictions that report in every month.

Individual plans

Individual plans leave out employer and union group coverage, so counts are smaller than in the county file.

Carrier share in Montana

Share of members whose contract has a carrier label, September 2026 against September 2025.

Contract file · Sep 2026
CMS contract file (SCC). All Medicare Advantage contracts, with employer and union group plans included. It still lists Connecticut and Alaska.

Humana leads with 69.4% of members who have a carrier label (contract file, September 2026).

Humana gained 14.5 points in 12 months; most of that change came in January 2026.

HCSC/BCBS lost 5.6 points in 12 months; most of that change came in January 2026.

UnitedHealthcare and Humana together hold 79.1%, up 5.4 points from Sep 2025.

The market is more concentrated than a year earlier (direction only; the level depends on how carriers are grouped).

Carrier share, Sep 2025 to Sep 2026

Percent of members with a carrier label. Largest carriers.

Carrier share, Sep 2025 to Sep 2026Slope chart comparing Sep 2025 with Sep 2026. Humana: 54.8% to 69.4%; HCSC/BCBS: 22.8% to 17.3%; UnitedHealthcare: 18.8% to 9.7%; Aetna/CVS: 1.8% to 1.8%; PacificSource: 1.2% to 1.4%; Elevance/Anthem: 0.4% to 0.4%.Sep 2025Sep 2026Humana 54.8%69.4% HumanaHCSC/BCBS 22.8%17.3% HCSC/BCBSUnitedHealthcare 18.8%9.7% UnitedHealthcareAetna/CVS 1.8%1.8% Aetna/CVSPacificSource 1.2%1.4% PacificSourceElevance/Anthem 0.4%0.4% Elevance/Anthem
Carrier share, Sep 2025 to Sep 2026Slope chart comparing Sep 2025 with Sep 2026. Humana: 54.8% to 69.4%; HCSC/BCBS: 22.8% to 17.3%; UnitedHealthcare: 18.8% to 9.7%; Aetna/CVS: 1.8% to 1.8%; PacificSource: 1.2% to 1.4%; Elevance/Anthem: 0.4% to 0.4%.Sep 2025Sep 2026Humana 54.8%69.4%Blue Cross 22.8%17.3%UHC 18.8%9.7%Aetna 1.8%1.8%PacificSource 1.2%1.4%Elevance 0.4%0.4%
View the data table
Carrier share, Sep 2025 to Sep 2026: Sep 2025 and Sep 2026
NameSep 2025Sep 2026Change
Humana54.8%69.4%+14.5 pts
HCSC/BCBS22.8%17.3%−5.6 pts
UnitedHealthcare18.8%9.7%−9.1 pts
Aetna/CVS1.8%1.8%0.0 pts
PacificSource1.2%1.4%+0.2 pts
Elevance/Anthem0.4%0.4%0.0 pts

Contract file · Sep 2026. Employer group plans included.

Carrier share of Medicare Advantage members with a carrier label, Montana, September 2026
CarrierShare, Sep 2026Share, Sep 2025ChangeMembers
Humana69.4%54.8%+14.5 pts55,345
HCSC/BCBS17.3%22.8%−5.6 pts13,764
UnitedHealthcare9.7%18.8%−9.1 pts7,729
Aetna/CVS1.8%1.8%0.0 pts1,441
PacificSource1.4%1.2%+0.2 pts1,103
Elevance/Anthem0.4%0.4%0.0 pts302
BCBS Michigan0.1%0.1%0.0 pts46
Regence/BCBS0.0%0.1%0.0 pts35
BCBS Minnesota0.0%0.0%0.0 pts19
All other carriers0.0%––0

Insurer not assigned in CMS data: 0.1% of all members in Sep 2026, 0.2% in Sep 2025. Shares leave these members out. Contract IDs are renumbered each January, so this page follows carriers, not contracts. A contract that serves several states carries one carrier label, so a carrier can appear in a state where it is not a local plan. See the carrier view for the whole nation.

Biggest counties in Montana

Individual plan members and the 12-month change for each county, from county data.

Individual MA · Sep 2026
Individual Medicare Advantage plans (IND), from county data. Employer and union group plans are left out, so counts are smaller than in the other two files.
Biggest counties in Montana by individual Medicare Advantage members, September 2026
CountyMembers12-month changeLeading carrierLeader's share
Yellowstone13,484+5.9%Humana67.2%
Flathead9,296+3.9%Humana69.7%
Cascade7,123+6.6%Humana81.5%
Missoula6,212−2.2%Humana75.1%
Lewis and Clark5,060+4.0%Humana86.9%
Gallatin4,730+3.0%Humana56.8%
Ravalli4,402−0.1%Humana64.8%
Lincoln3,249−4.6%Humana81.6%
Silver Bow2,448−0.8%Humana94.0%
Lake2,259−6.1%Humana68.3%

3 of 52 counties have no individual plan row. Those read "not reported", not zero. Browse all counties.

Common questions

How many people have Medicare Advantage in Montana?

Montana had 80,776 members in September 2026, by the CMS county file (employer group plans included). Individual plans, which leave out employer group coverage, had 73,154 members in September 2026.

Is Medicare Advantage growing in Montana?

Enrollment is up 1.0% from Sep 2025 to Sep 2026, slower than the national 2.0%. Among individual plans, which leave out employer group coverage, enrollment is up 2.4% in the 12 months to September 2026.

Which carrier has the most Medicare Advantage members in Montana?

Humana leads with 69.4% of members who have a carrier label (contract file, September 2026). UnitedHealthcare and Humana together hold 79.1%, up 5.4 points from Sep 2025. Shares leave out members whose contract has no carrier label: 0.1% of members.

Cite and download

Cite this page

Senior Deal Club Standards Desk. Medicare Advantage Enrollment in Montana, data as of September 2026. Source: CMS public enrollment files. https://www.seniordealclub.com/medicare-advantage/enrollment/states/montana

Download Montana CSV

Data: CMS public enrollment files, in a monthly snapshot processed by TapQuality. Senior Deal Club is not affiliated with Medicare or any government agency.

These pages are educational. They are not plan advice. How the numbers are built · Editorial policy