This study examines whether equity investors price the long-run fit between firms’ management accounting practices (MAPs) and their organizational lifecycle stages. We conceptualize fit as a slow-moving organizational attribute and decompose annual fit into (i) a persistent component capturing firms’ long-run alignment with lifecycle demands (Alignment), and (ii) transitory within-firm deviations (Deviation). Using Chinese A-share listed firms and implied cost of equity capital (COE) estimates, we find that higher long-run Alignment is associated with a significantly lower COE, whereas Deviation is not priced. Mechanism analyses suggest that Alignment is linked to lower operating risk, which in turn is associated with lower equity financing costs; in contrast, we find no evidence that the information risk mediates the relation. Cross-sectional tests further show that the pricing effect of Alignment is stronger when financing frictions are more severe. Overall, the evidence indicates that capital markets price firms’ long-run alignment of management accounting system design to lifecycle demands.