Our study challenges the belief that the mandatory bid rule (MBR) raises acquisition costs and deters takeovers. Leveraging the staggered adoptions of the mandatory bid rule (MBR) globally, we find that the MBR reduces the control premium, a key component of acquisition costs. Moreover, evidence does not support the claim that MBR discourages acquisitions above the threshold. While post-MBR ownership levels from block trades decline slightly, the likelihood of crossing the threshold remains unchanged. In the U.K., private deals above the threshold are fewer than below, but this gap is even larger in the U.S., which does not have an MBR.