Blue Apron has watched its shares plummet since going public as investors worry about the threat of Amazon. Capital World Investors held a nearly 13% stake in Blue Apron.

(Bloomberg)—Capital World Investors has sold its stake in Blue Apron Holdings Inc., a sign that investors are losing confidence in the beleaguered meal-kit delivery company that went public in late June.

Capital World Investors, a division of Capital Group, has fully exited its position in Blue Apron, No. 197 in the Internet Retailer 2017 Top 500, according to a Friday filing. The investment firm reported a 12.9% stake as of June 30, which had made it Blue Apron’s second largest investor, according to data compiled by Bloomberg.

New York-based Blue Apron has struggled to convince investors that its products will appeal to more than a niche audience and can also successfully overcome a looming threat from Inc. (No. 1) Since going public, Blue Apron’s shares have fallen more than 45%.

The company sells boxes of fresh food portioned to correspond with enclosed recipe cards and has been working to expand its meal-kit options to attract and retain customers. The June IPO failed to raise as much as originally expected, and Blue Apron has been forced to delay expansion plans.

In its first earnings report, the company revealed that it will need to spend more money on fulfillment centers and will continue to cut back on marketing that it has used to attract and retain customers. Blue Apron has since instituted a temporary hiring freeze and laid off a group of its recruiters. These revelations prompted more concerns about Blue Apron’s long-term sustainability and future prospects.

Blue Apron and Capital Group declined to comment.