How many months a new customer's gross-margin revenue takes to repay what you spent to acquire them, where efficient SaaS businesses usually clear it in under 18.
Shopify's prospectus disclosed that subscription gross-margin payback on customer acquisition cost was 14 months in 2014. The number anchored the IPO narrative as a 'capital-efficient SaaS' play, contrasting with the longer paybacks at Workday and ServiceNow and helping Shopify price above its initial range.
