LifePath Index 2070 Fund allocates and reallocates its assets among a combination of equity and bond index funds and money market funds (the “Underlying Funds”) in proportions based on its own comprehensive investment strategy.

LifePath Index 2070 Fund seeks to provide for retirement outcomes based on quantitatively measured risk. BFA employs a multi-dimensional approach to assess risk for LifePath Index 2070 Fund and to determine LifePath Index 2070 Fund’s allocation across asset classes. As part of this multi-dimensional approach, BFA aims to quantify risk using proprietary risk measurement tools that, among other things, analyze historical and forward-looking securities market data, including risk, asset class correlations, and expected returns. Under normal circumstances, the Fund intends to invest primarily in affiliated open‑end index funds and affiliated exchange-traded funds (“ETFs”).

LifePath Index 2070 Fund will invest, under normal circumstances, at least 80% of its assets in securities or other financial instruments that are components of or have economic characteristics similar to the securities included in its custom benchmark index, the LifePath Index 2070 Fund Custom Benchmark. LifePath Index 2070 Fund is designed for investors expecting to retire or to begin withdrawing assets around the year 2070. The Fund employs a “passive” management approach, attempting to invest in a portfolio of assets whose performance is expected to match approximately the performance of the Fund’s custom benchmark index. Certain Underlying Funds may invest in real estate investment trusts (“REITs”), foreign securities, emerging market securities, below investment-grade bonds, infrastructure, commodities and derivative securities or instruments, such as options and futures, the value of which is derived from another security, a currency or an index, when seeking to match the performance of a particular market index. The Fund and certain Underlying Funds may also lend securities with a value up to 331⁄3% of their respective total assets to financial institutions that provide cash or securities issued or guaranteed by the U.S. Government as collateral.

Under normal circumstances, the asset allocation will change over time according to a predetermined “glide path” as the Fund approaches its target date. The glide path below represents the shifting of asset classes over time. As the glide path shows, the Fund’s asset allocations become more conservative — prior to retirement — as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of the Fund, which may be a primary source of income after retirement.

LifePath Index 2070 Fund is one of a group of funds referred to as the “LifePath Index Funds,” each of which seeks to provide for retirement outcomes based on quantitatively measured risk that investors on average may be willing to accept given a particular time horizon. The following chart illustrates the glide path — the target allocation among asset classes as the LifePath Index Funds approach their target dates:

The following table lists the target allocation by years until retirement:

The asset allocation targets are established by the portfolio managers. The investment team, including the portfolio managers, meets regularly to assess market conditions, review the asset allocation targets of the Fund, and determine whether any changes are required to enable the Fund to achieve its investment objective.

Although the asset allocation targets listed for the glide path are general, long-term targets, BFA may periodically adjust the proportion of equity index funds and fixed-income index funds in the Fund, based on an assessment of the current market conditions, the potential contribution of each asset class to the expected risk and return characteristics of the Fund, reallocations of Fund composition to reflect intra-year movement along the glide path and other factors. In general, such adjustments will be limited; however, BFA may determine that a greater degree of variation is warranted to protect the Fund or achieve its investment objective.

BFA’s second step in the structuring of the Fund is the selection of the Underlying Funds. Factors such as fund classifications, historical risk and performance, and the relationship to other Underlying Funds in the Fund are considered when selecting Underlying Funds. The specific Underlying Funds selected for the Fund are determined at BFA’s discretion and may change as deemed appropriate to allow the Fund to meet its investment objective. See the “Details About the Fund — Information About the Underlying Funds” section of the prospectus for a list of the Underlying Funds, their classification into equity, fixed income or money market funds and a brief description of their investment objectives and primary investment strategies.

Within the prescribed percentage allocations to equity and fixed-income index funds, BFA seeks to diversify the Fund. The allocation to Underlying Funds that track equity indexes may be further diversified by style (including both value and growth), market capitalization (including large cap, mid cap, small cap and emerging growth), region (including domestic and international (including emerging markets)) or other factors. The allocation to Underlying Funds that track fixed-income indexes may be further diversified by sector (including government, corporate, agency, and other sectors), duration (a calculation of the average life of a bond which measures its price risk), credit quality (including non‑investment grade debt or junk bonds), geographic location (including U.S. and foreign-issued securities), or other factors. Though BFA seeks to diversify the Fund, certain Underlying Funds may concentrate their investments in specific sectors or geographic regions or countries. The percentage allocation to the various styles of equity and fixed-income Underlying Funds is determined at the discretion of the investment team and can be changed to reflect the current market environment.