Amazon has acquired a minority stake in Air Transport Services Group, an air freight partner that operates a significant stake in the company’s fast-growing aviation logistics unit.

Amazon has exercised warrants in ATSG that allow it to purchase approximately 13.5 million shares in the cargo airline at an exercise price of $ 9.73 per share, or more than $ 131.9 million, ATSG said in an SEC filed Monday . As part of a separate agreement, Amazon also bought around 865,000 ATSG shares without changing cash, the file says.

ATSG’s shares rose more than 4.9% in the early afternoon of Monday’s trading. Amazon stocks were largely unmoved.

Amazon has had warrants in ATSG since 2016. Warrants were granted as part of an agreement to lease 20 Boeing 767s from ATSG. This is one of the earliest contracts with a freight company to build its burgeoning air fleet. Amazon also has warrants to purchase a minority stake in rival airline Atlas Air Worldwide Holdings.

Launched in 2016, Amazon’s air fleet is a key part of the two-day and two-day delivery effort. The company still relies on ATSG and Atlas Air to fly a large portion of its packages, but has started bringing in some air freight operations, believing that Amazon Air could one day compete with FedEx and UPS, more Gives credibility.

In a first for the company, Amazon bought 11 used Boeing 767-300 jets from Delta and WestJet in January. The company is expected to lift the veil later this year at its $ 1.5 billion air hub in northern Kentucky, which can accommodate 100 Amazon-branded aircraft and is expected to handle approximately 200 daily flights.