Autonomous drone delivery just got a lot more valuable. Zipline raised $1.5 billion at a $21.5 billion post-money valuation, TechCrunch reports. Paradigm, WCM Investment Management and Layer Global led the round, joined by Valor Equity Partners, Fidelity, Uber, Tiger Global, J.P. Morgan, ARK Invest and Salesforce Ventures.

At the same time, Zipline and Walmart signed a multi-year agreement to add 300 drone delivery sites in the US, a big jump from the 21 they run together today in Texas and Arkansas. Walmart says its drone program has completed more than 2 million deliveries, Quartz reports.

Zipline was valued at $7.6 billion when it raised more than $600 million in January. It plans to spend the new money on US manufacturing and hiring to build a nationwide delivery network.