@saper If someone buys advertising on DuckDuckGo, it goes via the Bing network, so that could be it..
https://duck.co/help/company/advertising-and-affiliates "The advertising we syndicate through Yahoo! is part of the Yahoo-Microsoft search alliance. By default, when you sign up for a Bing Ads account, your ads should automatically enter rotation into all of Bing's distribution channels including DuckDuckGo."
@saper Depends to which other search-engine you're comparing. If it's the ubiquitous, warfare-software-producing one, it could very well be they're suppressing rival companies in the results. DuckDuckGo provides fairly well privacy, I use searx.me though, for the reasons described in: