Amazon just upped the ante for the retail industry once again, saying it is moving fast to evolve its signature two-day free shipping for Prime members into one-day free shipping.

“This is a big investment,” said Brian Olsavsky, Amazon’s chief financial officer.

Amazon plans to spend an incremental $800 million in Q2 alone—that’s more than one-fifth of its net income in Q1—on this new initiative, with plans to build out the “capacity” the rest of this year, Olsavsky said. In the past month, Amazon “significantly” expanded the selection of products and zip codes eligible for one-day shipping, he said.