Amazon's Deliveroo investment is a bad sign for Uber — shares of an Uber Eats rival are tanking

Amazon has led a $575 million financing round into Deliveroo, one of Uber Eats' archrivals.Uber went public last week and saw its stock plunge 8% on its first day of trading.Uber Eats had much larger revenue than Deliveroo at last count, and nearly three times the number of restaurant partners.The news sent shares in Just Eat, another meal-delivery competitor, down 7%.Watch Uber, Amazon, and Just Eat trade live.Uber's week just got worse. Days after the ride-hailing giant went public and saw its stock plunge 8% on its first day of trading, Amazon has invested in Deliveroo, the archrival of Uber's meal-delivery service, Uber Eats, in the UK.The news sent shares down 7% in Just Eat, wiping more than £360 million off the market cap of the third major food-delivery company in the UK.Amazon led a $575 million financing round into Deliveroo, potentially making the e-commerce giant one of the meal courier's largest investors. Deliveroo, which works with more than 80,000 restaurants and takeaways and 60,000 delivery riders, has raised just over $1.5 billion to date. It operates in more than 500 towns and cities across 14 markets including Australia, Hong Kong and the United Arab Emirates.Deliveroo will have its work cut out to topple its much larger rival. Uber Eats has partnered with more than 220,000 restaurants across upward of 500 cities. It generated net revenue of $587 million in 2017, while Deliveroo's annual revenue was £277 million ($354 million) that year. Uber Eats is also growing quickly: its net revenue surged by nearly 150% to almost $1.5 billion in 2018.Amazon joined existing Deliveroo investors T Rowe Price, Fidelity, and Greenoaks Capital in the Series G funding round. Deliveroo plans to use the additional funds to hire more engineers at its London headquarters, expand into new areas to reach new customers, and ramp up “Editions” — its delivery-only super kitchens.“This new investment will help Deliveroo to grow and to offer customers even more choice, tailored to their personal tastes, offer restaurants greater opportunities to grow and expand their businesses, and to create more flexible, well-paid work for riders,” said Deliveroo's founder and CEO Will Shu.“We're impressed with Deliveroo's approach, and their dedication to providing customers with an ever increasing selection of great restaurants along with convenient delivery options,” said Doug Gurr, Amazon UK Country manager. “Will and his team have built an innovative technology and service, and we're excited to see what they do next.”