An income base step-up is an increase to the notional benefit base used by certain annuity income riders (such as guaranteed withdrawal benefits) to calculate future income. Step-ups are typically triggered on contract anniversaries when the account value exceeds the current base, locking in market gains for future income calculations. The base is not a cash-accessible value; it is a measurement used with rider percentages to determine allowed withdrawals. Step-ups interact with roll-ups, withdrawal timing, and rider fees. Understanding step-up rules helps align expectations about future income, especially when markets are volatile and actual account value diverges from the income base over time.

During annual reviews, advisors check whether the account value exceeds the income base and whether a step-up will lock in gains. They coordinate step-ups with timing of withdrawals to maximize lifetime income without violating rider rules.