We model the production of complex goods in a large supply network. Each firm sources several essential inputs through relationships with other firms. Individual supply relationships are at risk of idiosyncratic failure, which threatens to disrupt production. To protect against this, firms multisource inputs and strategically invest to make relationships stronger, trading off the cost of investment against the benefits of increased robustness. A supply network is called fragile if aggregate output is very sensitive to small aggregate shocks. We show that supply networks of intermediate productivity are fragile in equilibrium, even though this is always inefficient. The endogenous configuration of supply networks provides a new channel for the powerful amplification of shocks.

翻译：我们在大规模供应链网络中对复杂商品的生产进行建模。每个企业通过与其他企业的关系获取若干关键投入要素。个体供应关系面临特质性失效风险，这可能中断生产。为防范此类风险，企业采取多源采购策略并进行战略性投资以强化合作关系，在投资成本与增强稳健性带来的收益之间进行权衡。当总产出对微小总体冲击极为敏感时，该供应链网络被称为脆弱的。研究表明，即使这始终是低效的，中等生产率的供应链网络在均衡状态下仍会表现出脆弱性。供应链网络的内生结构为冲击的强力放大提供了新渠道。