A Beginner's Tutorial for Fixed Index Annuities. Written by Hersh Stern Updated Monday, February 17, 2020 A Fixed Index Annuity is a tax-favored accumulation product issued by an insurance company.It shares features with fixed deferred interest rate annuities; however, with an index annuity, the annual growth is bench-marked to a stock market index (e.g., Nasdaq, NYSE, S&P500) rather than an Be sure your annuity issuer has the ability to pay, because you are not guaranteed anything on a Federal or State level with regards to earnings from Riders, unlike some of your principal, which is guaranteed to a certain extent. The insurance carrier will use account B as the income calculation base to determine the amount your monthly payments will be (Income calculation base, or benefit base).