(Bloomberg) — Health insurers won a victory in 2015 when a tax that was part of the Affordable Care Act was suspended. Now as they fight to repeal or delay the tax again before it comes back into effect, the odds don’t seem to be in their favor.

Insurers, businesses and conservative groups are scrambling for ways to at least delay the health insurance tax, or HIT, following the collapse of health-care legislation in July. They seemed poised for victory just a few months ago, when the health-insurance fee, and most of the other levies enacted to help fund Obamacare, were targeted in repeal bills passed by House Republicans and considered by Senate Republicans.

The health-insurance tax, which is scheduled to go back into effect in December, is an annual fee owed by insurers such as Anthem Inc., UnitedHealth Group Inc. and Aetna Inc. that varies based on their share of net premiums written nationally -- the aggregate amount owed would total $14.3 billion in 2018. Those opposed to the tax are trying to pitch the message that repealing it could prevent higher premium costs for consumers.