Building a first-year MA plan's network.

A first-year Medicare Advantage application is a build on a fixed CMS deadline with no flexibility. The plan year begins January 1. CMS requires the application — including network submission — to be filed by a date that falls months before the plan year begins. Between the CMS submission deadline and the go-live date, there is a network validation (NV) review process that can surface adequacy problems requiring remediation, on a timeline that doesn't leave much room for fixes.

Organizations that underestimate the compression of this timeline don't build with enough margin. That leads to either a missed submission deadline (which means waiting another year), a submitted application with an inadequate network (which fails the NV review), or a frantic final push that produces contracts that are signed but not credentialed.

The CMS application timeline

CMS publishes the MA application dates every year. They shift by a few days, but the structure holds. Using the dates CMS set for contract year 2027:

• Early January: CMS posts the application in HPMS (January 7, 2026 for CY2027). The Notice of Intent to Apply is due later that month.
• Mid-February: The application is due (February 11, 2026 for CY2027). Since contract year 2024, a new or expanding plan must demonstrate network adequacy as part of the application, through HSD tables listing providers and facilities with executed contracts or, during the application review only, a letter of intent signed by both parties.
• Spring: CMS reviews the HSD tables in rounds. Deficiencies come back to the plan, which can add contracted providers or request exceptions.
• First Monday in June: Bids are due.
• Late summer: CMS finalizes contracts with approved plans.
• October: Marketing opens October 1, and the Annual Enrollment Period runs October 15 through December 7.
• January 1: Plan year begins. Members are enrolled. Claims start flowing.

Sources: CMS CY2027 Part C application; 42 CFR 422.116. Confirm each year's dates in the current HPMS memos.

This means the network you submit in February needs to be substantially built, not in progress. HSD tables can list providers with executed contracts or, while CMS reviews the application, a letter of intent signed by both parties. Every LOI has to become an executed contract by January 1, and applicants that use LOIs get a full network review in their first operating year. An LOI buys time on paperwork, not on negotiation, so the contracting and credentialing work still has to start by the middle of the prior year, roughly eight months before the application is due. For a January 1 launch, that puts the start of the build about a year and a half before go-live.

The network validation review

CMS network validation is not a pass/fail review with a clean outcome — it is an iterative process where CMS identifies specific adequacy gaps and asks the plan to address them. The response options are: submit additional contracted providers who fill the gap, request an exception (where the providers CMS expects you to use aren't actually available), or dispute the finding.

First-time applicants often underestimate how specific the NV deficiencies are. CMS identifies gaps at the county level, by specialty, by the specific time-distance standard that was not met. “We have adequate primary care coverage” is not a response. “Here are the two additional primary care contracts we executed since submission, which fill the gap in County X” is a response. The specificity of the deficiencies requires you to have additional contracting capacity held in reserve to respond to NV findings — you cannot commit your entire contracting pipeline to the initial submission and have nothing left for remediation.

The HSD table submission format

CMS has specific requirements for how provider data is submitted with the application. The HSD tables list every contracted provider and facility, with NPI, the CMS HSD specialty code and the address where they see patients. Errors in those tables (the wrong specialty code, addresses that don't geocode correctly, providers listed without an executed contract or a signed LOI) create deficiencies that you have to respond to.

Running a validation pass on your HSD tables before submission is not optional. It is the only way to catch data quality problems before CMS does. Common issues: HSD specialty codes that don't match the specialty the provider actually practices (CMS crosswalks its codes from Medicare specialty codes, so a wrong taxonomy upstream can land a provider in the wrong one), practice location addresses that are building addresses rather than suite-level addresses that geocode to the correct location, and NPI numbers for providers who have been deactivated in the NPPES registry.

The NV review is not a technicality. It is CMS looking at your network through the same lens that will determine whether your members can actually access care. Submit a clean file.

First-year credentialing capacity

First-year plans often don't have a credentialing committee yet — they are building the governance structure at the same time they are building the network. This is a legitimate operational challenge. Options include: delegating credentialing to a hospital or medical group that has an existing NCQA-certified credentialing program, contracting with a credentialing verification organization (CVO) to run the process, or establishing your own committee and policies that meet CMS credentialing rules at 42 CFR 422.204, with NCQA accreditation as an optional later step.

Whatever the approach, the credentialing infrastructure needs to be in place before the first contracts are executed — not simultaneously, and not after. Contracting ahead of your credentialing capacity produces a large backlog that you will spend the rest of the build trying to clear.

Sources: 42 CFR 422.116 (letters of intent at (d)(7); exceptions at (f)); CMS network adequacy guidance, December 2024; 42 CFR 422.204 (provider selection and credentialing).