**Yes—generally, you can keep investing in a 2040 target-date fund after 2040**, provided the fund remains available and you remain eligible to contribute to your retirement account. The year guides the fund’s investment mix; contribution eligibility comes from your account or plan’s rules. A target-date fund is an investment held inside that account. [SEC explanation](https://www.investor.gov/introduction-investing/introduction-investing-basics/investment-products/mutual-funds-and-exchange-traded-6)

After 2040, your money stays invested. What happens to the mix of stocks and bonds depends on the fund:

- A **“to retirement”** fund generally reaches its final, conservative mix around 2040.
- A **“through retirement”** fund continues becoming more conservative for several years afterward.

That schedule follows the fund’s target date even if you keep working until 2043. [SEC target-date fund bulletin](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/target-date-funds-investor-bulletin)

Some providers eventually merge older target-date funds into a retirement income fund. For example, Vanguard expects such combinations within seven years after the target year; shareholders receive shares in the income fund. [Vanguard prospectus](https://personal1.vanguard.com/pub/Pdf/p308.pdf)

**For choosing between 2040 and 2045, compare funds from the same provider:**

| Choice | Typical tradeoff |
|---|---|
| **2040** | Becomes conservative sooner, with generally less stock exposure and lower growth potential. |
| **2045** | Holds more stocks for longer, with greater growth potential and greater exposure to market declines. |

These differences vary by provider, so check each fund’s stock/bond allocation and fees. [SEC guidance](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins/target-date-funds-investor-bulletin)

If **2043 is your best estimate**, 2045 is a reasonable starting choice because it is closer to your expected retirement year. If you prefer a more conservative investment mix, 2040 may suit you better. Either can fit a retirement window of 2040–2045, and you can reassess as your plans become clearer.