An index account is a crediting option within indexed universal life (IUL) policies or fixed indexed annuities (FIAs) that credits interest based on the performance of an external index over a segment term, subject to caps, spreads, or participation rates. Index accounts typically reset annually or biennially, locking in credited interest and applying a floor (often 0%) against market losses. They coexist with fixed accounts that credit a declared rate. Allocation among available index accounts influences potential accumulation and volatility of credited interest.

Advisors diversify IUL allocations across index accounts with different caps, participation, and durations. Annual reviews reallocate based on renewal terms and client objectives, documenting changes in the service file.