Using a panel of self-declared benchmarks, we examine funds’ use of mismatched benchmarks over time. Mismatching is high at the beginning of our sample (45 % of TNA in 2008), consistent with prior studies, but declines significantly over time (27 % in 2020), driven by existing specialized funds changing benchmarks to match their style. Market forces including investor learning, institutional governance, market competition, and product positioning all play a role in benchmark correction decisions. For funds with difficult to categorize investment strategies, mismatched benchmarks are less associated with performance bias. Our study highlights the value of market solutions in aligning manager-investor interests.