The Federal Retirement Thrift Investment Board (FRTIB), the agency that oversees the Thrift Savings Plan (TSP), approved a change to the underlying index tracked by the I Fund in November 2023. The new index is the MSCI ACWI IMI ex USA ex China ex Hong Kong Index. This index is a collection of large, mid, and small-cap stocks in developed and emerging markets countries, but it excludes
investments from China, Hong Kong, and the United States. That last point is key given the controversy of the last proposed change to the I Fund index.

The new index will expand the diversity of investment options within the I Fund. According to Aon, the consulting firm the FRTIB used to evaluate the benchmark indices within the TSP, the new I Fund index will expand coverage of non-US equity markets from 55% under the current MSCI EAFE Index to 90% under the new MSCI ACWI IMI ex USA ex China ex Hong Kong Index. The current MSCI EAFE index invests in 798 large and mid-cap stocks in twenty-one developed countries. The new index invests in 5,621 large, mid, and small-cap stocks in twenty-one developed and twenty-three emerging markets.

According to the FRTIB, the transition is currently scheduled to take place in 2024. They cannot disclose exact timing in advance because they need to protect the fund from the potential for other investors to have an unfair trading advantage. They will announce when the transition to the new benchmark index is complete, which will be no later than December 31, 2024.