Indexed universal life (IUL) explained

Indexed universal life (IUL) is a universal life policy whose cash account earns interest based partly on the performance of a stock market index such as the S&P 500, subject to a cap on gains and a floor, usually 0%, on losses. Your money is not invested in the index; the insurer credits interest by formula. It is a life insurance policy first, with monthly charges that continue for as long as you hold it.

How IUL works

The basic mechanics are the same as any universal life policy: premiums go into an account, the insurer deducts the cost of insurance and fees each month, and the balance is credited with interest. What differs is the crediting. You choose how to allocate the account among:

• A fixed account, which earns a declared rate like standard universal life.
• One or more index accounts, which earn a credit calculated from an index's change over a period, usually one year, using an index crediting method.

At the end of each crediting period the insurer applies a formula, built from a cap, a participation rate or a spread, and a floor. IUL caps, participation rates and floors walks through each with examples. Behind the scenes the insurer typically buys options on the index with a fixed budget, which is why gains are limited. The insurer, not you, owns those options.

What the index does not include

Most IUL index accounts track a price index, which excludes dividends. Some policies offer volatility-controlled or proprietary indices designed to smooth returns, often paired with higher caps or a multiplier but with a different return profile. A credit tied to an index is not the same as the index's total return, and the long-term average credit is lower than the headline average of the index. A policy's actual crediting history, over a period of 10 or more years, is what to examine, with the specific index and cap in force for each year.

What it costs

IUL is a permanent policy, and the main costs are:

• Cost of insurance, which rises with age and is usually the largest charge later in life.
• Premium load or expense charge, a percentage of each premium, plus a monthly per-policy administrative fee and sometimes a per-thousand charge on the face amount.
• Rider charges, for example for a chronic illness or no-lapse rider.
• Surrender charges, usually for the first 10 to 15 years. See life insurance surrender charges explained.

fees and charges inside permanent life insurance covers these in more detail. Because charges come out every month regardless of index results, a year with a 0% credit still reduces the account. A floor protects against index losses, not against costs.

Loans and "tax-free income"

IUL is widely sold as a source of tax-free retirement income by taking policy loans from the cash value. The tax treatment is real: a loan from a policy that is not a modified endowment contracts and the 7-pay test is generally not taxable income as long as the policy stays in force. The risks are also real. Interest accrues on the loan, a participating (indexed) loan can lose the credits you expected on the borrowed amount, and if the policy lapses with a loan outstanding, the gain can be taxable. how cash value is taxed: withdrawals, loans and surrenders explains the rules, and overloan protection riders: how they prevent a taxable lapse describes one safeguard. See using life insurance for retirement income for the broader strategy.

Illustrations and Actuarial Guideline 49

Because the credits are not guaranteed, buyers are shown an policy illustration with an assumed rate. The NAIC adopted Actuarial Guideline 49 in 2015 to put the first uniform limits on the illustrated rate and on loan leverage, and amended it as AG 49-A in 2020 and again in 2023. According to Lincoln Financial's AG 49 summary, a further amendment adopted in November 2025 took effect April 1, 2026, restricting the historical data shown in illustrations to indices at least 10 years old and restricting side-by-side comparisons of historical averages against the maximum illustrated rate. The 2023 version requires non-benchmarked accounts, such as volatility-controlled indices, to illustrate no better than a benchmark index account.

These limits make illustrations more conservative but not predictive. The illustration still assumes a steady rate every year, while real credits vary, and the results depend on the insurer holding its caps and charges. See IUL illustrations and Actuarial Guideline 49 and how to read a life insurance illustration.

How common is it

According to LIMRA's 2025 sales results, released in March 2026, IUL new premium reached a record $4.5 billion in 2025, up 17% from 2024, about 25% of U.S. individual life new premium. LIMRA attributes the growth to expanded distribution, enhanced products and a strong equity market. Popularity is not evidence of fit; premium share reflects, in part, how heavily the product is marketed and the commissions it pays. See how life insurance agents are paid.

Who it suits

IUL may suit a buyer who wants lifelong coverage, can fund it at a level that keeps it from lapsing, understands that the credited rates and charges are non-guaranteed, and has already used lower-cost options such as employer retirement plan matches. It suits people less well if the main goal is investing, if they cannot sustain high premiums for 15 or more years, or if they want guarantees; guaranteed universal life: permanent coverage without the cash and whole life give more certainty. For the arguments on each side, read IUL pros and cons: what the sales pitch leaves out; for comparisons with retirement accounts, read IUL vs 401(k): why the comparison misleads and IUL vs Roth IRA for tax-free retirement income.

Questions to ask before buying

1. What are the current cap, participation rate and spread on each index account, and what are the guaranteed minimums?
2. What does the guaranteed illustration column show, and when does the policy lapse in it?
3. What are the total monthly charges at ages 55, 65 and 80?
4. How long are surrender charges, and how much of the cash value would I receive if I stopped paying at year 10?
5. What type of loan is available (fixed or participating), and at what rate?

Use the questions to ask a life insurance agent list and compare answers across insurers.

Key takeaways

• IUL is universal life that credits interest by formula from an index, with a cap on gains and usually a 0% floor.
• Charges are deducted every month, including in years with a 0% credit; the floor does not protect against costs.
• Illustrations are limited by NAIC Actuarial Guideline 49 and its amendments, but they still show non-guaranteed, steady-rate projections.
• Loans can provide tax-advantaged access to cash value, with real lapse and tax risks.