FPGA-based floating-point kernels must exploit algorithmic parallelism and use deeply pipelined cores to gain a performance advantage over general-purpose processors. Inability to hide the latency of lengthy pipelines can significantly reduce the performance or impose unrealistic buffer requirements. Designs requiring reduction operations such as accumulation are particularly susceptible. In this paper we introduce two high-performance FPGA-based methods for reducing multiple sets of sequentially delivered floating-point values in optimal time without stalling the pipeline.