The $25M annual cost of maintaining Jeff Bezos' superyacht Koru underscores the extreme expenses tied to the world’s most luxurious vessels, even as sustainable technology becomes a factor. Koru is a 127-meter (417-foot) long sailing yacht, making it the largest sailing yacht in the world. It was built by Dutch shipyard Oceanco and delivered in 2023. It is estimated to have cost around $500 million to build.