How do you determine the second lowest cost Silver plan (SLCSP) if there are no Silver plans available in your area?

No, the absence of Silver plans does not eliminate your subsidy.

​The system is designed to provide a substitute value. If no Silver plans are available in your area, the Marketplace (HealthCare.gov or state exchange) will designate a hypothetical Second Lowest Cost Silver Plan (SLCSP) premium.

​This non-zero proxy value is used in the subsidy calculation, ensuring you still qualify for the Premium Tax Credit (PTC) which you can apply toward the available Bronze or Gold plans. You will receive this proxy amount on Form 1095-A.

According to Publication 974 (2024), Premium Tax Credit (PTC) :

Applicable SLCSP premium tools.

Only the Marketplaces are able to provide applicable SLCSP premiums. The federally facilitated Marketplace and most state Marketplaces have provided applicable SLCSP premium tools that, as you prepare your tax return, you may use to look up the SLCSP premium that applies to your coverage family for each month. If you enrolled through the federally facilitated Marketplace, you will find the tool at HealthCare.gov/Tax-Tool/.

If you enrolled through a state-based Marketplace, you may find information about whether your state has an applicable SLCSP premium tool on the state-based Marketplace’s website. If the website does not have an applicable SLCSP premium tool, you will need to contact the state-based Marketplace directly for the correct SLCSP premium.

It is the responsibility of the official federal/state marketplace to determine the SLCSP that applies to all locations and family sizes. Of course if you are not applying for the tax credit, then you have no need to determine the SLCSP that applies to your exact situation..