The incorporation of broadcast and multimedia-on-demand services are expected to increase multicast traffic in packet networks, and therefore in switches and routers. Combined input-crosspoint buffered (CICB) switches can provide high performance under uniform multicast traffic, however, at the expense of N2 crosspoint buffers. In this paper, we introduce an output-based shared-memory crosspoint-buffered (O-SMCB) packet switch where the crosspoint buffers are shared by two outputs and use no speedup. The proposed switch provides high performance under admissible uniform and nonuniform multicast traffic models while using 50% of the memory used in CICB switches. Furthermore, the O-SMCB switch provides higher throughput than an SMCB switch with buffers shared by inputs, or I-SMCB, previously proposed, despite the strong similarities between the architectures of these two switches. In this paper, we study the performance of the O-SMCB switch under uniform and nonuniform multicast traffic models and compare it to the I-SMCB switch.