Which rider does NOT guarantee an income benefit?

The Guaranteed Minimum Accumulation Benefit (GMAB) is designed to ensure that the investor's account value will reach a minimum threshold by a certain date, typically at the end of a specified period. This rider is primarily focused on the accumulation of assets rather than providing a guaranteed income stream. Therefore, it does not guarantee any type of income benefit upon withdrawal or during retirement.

In contrast, the other riders mentioned are tailored to provide some level of income assurance. The Guaranteed Lifetime Withdrawal Benefit (GLWB) provides a contractual guarantee for withdrawals for the lifetime of the annuitant, ensuring a consistent income. The Guaranteed Minimum Income Benefit (GMIB) guarantees a minimum income amount based on the annuitant’s investment, generally upon annuitization, and the Guaranteed Minimum Withdrawal Benefit (GMWB) provides the assurance of being able to withdraw a certain amount over time while still preserving the principal value.

Thus, the GMAB's focus on asset accumulation rather than income makes it the correct answer to the question regarding which rider does not guarantee an income benefit.