We document the recent rise in the side-by-side (SBS) management of mutual funds and actively managed ETFs (AMETFs). Although these funds are run in a SBS manner, only 21% share an investment objective code. This relationship is started by families with more ETF experience and is not used to reward "star" managers. On average, mutual funds with SBS AMETFs perform similarly to comparable funds after SBS formation; however, their flows fall when pairs share the same investment objective. We find evidence of both a substitution effect and conflicts of interest between SBS funds, depending on the contracting and organizational structures.