Index Universal Life (IUL) insurance is a form of permanent life insurance that offers both a death benefit and a cash value component. The cash value growth is linked to the performance of a specified stock market index, providing the potential for higher returns compared to traditional whole life insurance. Unlike variable universal life insurance, which directly invests in stocks, the cash value in an IUL policy is not directly invested in the stock market but instead earns interest based on the index's performance, with protections against market downturns.