The Investment Company Institute reported that the combined assets of all Section 529 plans increased by 8.39% year-to-date (YTD) from $602.9 billion on December 31, 2025, to $653.5 billion on June 30, 2026 (latest available data). The number of Section 529 plan accounts was 18.2 million at the end of June, an increase of 2.71% YTD from roughly 17.7 million at the start of the year.