Mutual funds managed by firms that also manage hedge funds tend to perform worse than mutual funds not affiliated with hedge funds. This underperformance is mainly due to differences in return gaps, which reflect hidden managerial actions. Interestingly, mutual funds with investment styles similar to affiliated hedge funds show the biggest underperformance. Additionally, these side-by-side mutual funds do not benefit as much from IPO underpricing as unaffiliated mutual funds or affiliated hedge funds. Overall, there is no clear evidence that affiliations with hedge funds help side-by-side mutual funds attract better stock-picking talent, and it is possible that management firms prioritize maximizing fee income over maximizing mutual fund performance.