Target-Date Funds: What Is Inside the Glide Path

Target-date funds have become the default choice inside millions of 401(k) accounts since Congress passed the Pension Protection Act of 2006. That law made these funds a qualified default investment alternative, so plan sponsors could automatically enroll workers without fear of fiduciary liability if the funds followed a sensible glide path. By 2026 roughly two-thirds of new 401(k) contributions flow into target-date options according to industry tallies. The idea is simple: pick the fund that matches your expected retirement year and the manager handles the asset allocation shifts for you.

Yet the label on the box tells only part of the story. Two funds both labeled 2045 can hold equity allocations that differ by 15 percentage points or more because one follows a to-retirement design while the other uses a through-retirement approach. Expense ratios also vary because each layer of underlying mutual funds or ETFs adds its own fee even when the headline number looks low. Understanding what sits inside the glide path helps a saver decide whether the automatic choice truly matches personal risk tolerance and retirement timeline.

The Glide Path in Plain Numbers

A typical target-date fund starts with roughly 90 percent equities when the worker is in their twenties and gradually reduces stock exposure as the target year approaches. By the retirement year itself many funds reach an equity share between 30 percent and 50 percent. The exact landing point depends on whether the fund is designed to reach that mix at the target date or to keep gliding more slowly afterward. The Pension Protection Act of 2006 never dictated a single glide path, only that the default had to be age-appropriate and diversified.

Glide paths are usually shown on a chart that slopes downward in a straight line or gentle curve. Early in a career the high equity stake captures long-term growth. As decades pass the manager sells stocks and buys bonds to limit sequence-of-returns risk near retirement. Critics argue that many glide paths de-risk too quickly for a retirement that can last 25 or 30 years, yet plan sponsors keep favoring the smoother ride because participants rarely complain about missed gains.

Vintage Years and Five-Year Increments

Target-date funds are offered in five-year increments such as 2030, 2035, 2040, 2045 and so on up to 2065 or later. The vintage year is the year the fund expects the investor to stop working. A 30-year-old in 2026 would normally choose the 2060 or 2065 fund. The underlying mix inside each vintage is reset once per year or once per quarter so everyone in that bucket receives the same allocation regardless of exact birth date.

This bucket approach simplifies administration inside 401(k) plans but creates a blunt instrument. Someone planning to retire at 62 and another planning to work until 70 might both land in the same 2040 fund even though their optimal equity exposure should differ. The five-year steps mean the actual glide path for any individual is only approximate.

To-Retirement Versus Through-Retirement Designs

To-retirement funds reach their most conservative mix in the target year and then hold that allocation forever. Through-retirement funds keep reducing equity exposure for another 10 to 30 years past the target date, sometimes landing as low as 20 percent stocks. The difference matters because a 65-year-old who still has a long life expectancy may need more growth than a static 40-60 mix can deliver.

Plan sponsors must document which design they chose when they select a series of target-date funds. The Pension Protection Act of 2006 requires that the qualified default investment alternative be reviewed periodically for continued suitability. A participant who wants the other design must usually opt out and build their own mix or choose a different fund family.

What Happens at and After the Target Year

On the target date the fund does not automatically liquidate and mail a check. The investor can leave the money inside the same fund and it will continue to follow whatever glide path the manager set. Required minimum distributions under SECURE 2.0 begin at age 73, so the account must start sending money to the participant whether the asset mix feels right or not.

Layered Fund-of-Funds Fees

Most target-date funds are built as a fund of funds. The headline expense ratio includes the cost of the target-date wrapper plus the weighted average expense ratios of the underlying stock, bond and international funds. Typical index fund expense ratios run from 0.03 percent to 0.20 percent while active underlying funds can cost 0.5 percent to 1.0 percent. The combined fee on a target-date fund therefore often lands between 0.08 percent and 0.70 percent depending on how much active management is used inside.

That layered structure means even a low-looking headline number can hide multiple management fees. The 401(k) saver pays the total expense ratio every year on the entire balance, which compounds over decades. The Pension Protection Act of 2006 did not set fee limits, only that the default had to be prudent. Participants should compare the all-in cost across different vintages and providers before assuming the cheapest headline number is the best deal.

• The glide path determines how much market risk a saver carries at each life stage.
• Two funds with the same 2040 vintage can hold equity allocations that differ by 15 percentage points or more.
• To-retirement designs stop de-risking at the target year while through-retirement designs continue for another decade or longer.
• Layered fees from underlying funds add to the headline expense ratio even when the target-date wrapper itself is inexpensive.
• The Pension Protection Act of 2006 gave plan sponsors a safe harbor when they default workers into these funds.
• Investors should read the fact sheet for their specific vintage to see the exact equity and bond targets at retirement.

Target-date funds remove the need to rebalance every year but they are not all created equal. A saver who understands the glide path, the design choice and the true cost can decide whether the default option fits or whether a custom mix using low-cost index funds would serve better over a 40-year horizon.