IUL is the modern incarnation of the cash-value sales pitch. It is also the product most aggressively marketed at higher-income prospects through “infinite banking,” “Bank On Yourself,” and similar branded curricula. The structural pitch is appealing: cash value credited to a stock index (S&P 500 most commonly) with a floor (typically 0%, so “no losing years”) and a cap (typically 8%–12%). The pitch implies you get the upside of equities without the downside. You do not.
Where the IUL math actually lands. Three contractual levers compress the equity-like return into something that resembles a corporate bond after fees:
Crediting is capped at the cap rate, declared annually by the carrier and contractually adjustable downward. A 10% cap turns a 20% index year into 10%. Carriers have systematically lowered caps over the policy life — the 12%–14% caps common at sale in 2014–2018 ran 7%–9% by 2024.
Many designs credit only a percentage of the index move (e.g., 80% participation). Combined with the cap, an index gain of 20% becomes 0.8 × min(20%, cap) credited.
The index is the price index (no dividends). The S&P 500’s roughly 1.5% trailing dividend yield disappears from your crediting calculation; the carrier keeps it.
On top of those, the COI is debited monthly from the cash value, rising with attained age and escalating sharply after age 70. The combined effect is that long-run IRR on a typical illustrated IUL policy runs 3%–5% before the death-benefit drag is netted in — bond-like returns sold as equity-like returns. The 0% floor is real but priced; you are paying for it explicitly through the cap and participation rate, not getting it for free.
The agent-conflict signal. If a wealth advisor or insurance broker is leading with IUL as a tax-free retirement income vehicle, treat that as a strong negative signal about the relationship. The advisor’s economics on an IUL sale — typically 70%–110% of the first year’s target premium as compensation — are larger than on essentially any other personal financial product. The implication is not that the product is illegal; it is that the incentive structure pulls the advisor toward selling it whether or not it fits, and that an reader who hears the pitch should get a second opinion from an advisor on flat fees.