The “to” and “through” each represent the point in a Target Date Funds’ glide path where its asset allocation to public equity becomes its most conservative. Some target date fund investment models are based on a "to retirement" concept, which help the investor earn enough money to get them to retirement so they can then use those funds as a source of income during their retired years. “To retirement” glide paths reach this point sometime on the assumed retirement date. “Through retirement” glide paths reach this point sometime after the assumed retirement date.
The new model of "through retirement" seeks higher returns during their working years as well as during their retirement years compared to the old asset allocation. The new Target Date Fund allocation will reach its most conservative point at an assumed age of approximately 75, or ten years after the assumed retirement age.
Both “to” and “through” glide paths are designed to earn positive returns in retirement. “Through” constructed glide paths usually target higher expected returns than “to retirement” glide paths in order to combat longevity and shortfall risks.