A fuel cell stack module includes a plurality of fuel cell stacks, an anode tail gas oxidizer (ATO) which is located in a heat transfer relationship with the plurality of fuel cell stacks, a base supporting the plurality of fuel cell stacks and the ATO, and at least one heat exchanger located in the base. An ATO exhaust stream and an anode exhaust stream from the fuel cell stacks heat the stack fuel and air inlet streams in a multi-stream heat exchanger.