Yahoo! Search is a Yahoo! internet search provider that uses Microsoft's Bing search engine to power results, since 2009, apart from four years with Google from 2015 until the end of 2018. Originally, "Yahoo! Search" referred to a Yahoo!-provided interface that sent queries to a searchable index of pages supplemented with its directory of websites. The results were presented to the user under the Yahoo! brand. Originally, none of the actual web crawling and data housing was done by Yahoo! itself. In 2001, the searchable index was powered by Inktomi and later by Google until 2004, when Yahoo! Search became independent. On July 29, 2009, Microsoft and Yahoo! announced a deal in which Bing would henceforth power Yahoo! Search. As of July 2018, Microsoft Sites handled 24.2 percent of all search queries in the United States. During the same period of time, Oath (the then-owner of the Yahoo brand) had a search market share of 11.5 percent. Market leader Google generated 63.2 percent of all core search queries in the United States. Yahoo! Search was criticized for favoring websites owned by Yahoo!'s then-parent company, Verizon Media, in its search results. In September 2021, investment funds managed by the private equity firm Apollo Global Management acquired 90% of Yahoo. The roots of Search date back to Yahoo! Directory, which was launched in 1994 by Jerry Yang and David Filo, then students at Stanford University. In 1995, they introduced a search engine function, called Yahoo! Search, that allowed users to search Yahoo! Directory. it was the first popular search engine on the Web, despite not being a true Web crawler search engine. They later licensed Web search engines from other companies. Seeking to provide its own Web search engine results, Yahoo! acquired their own Web search technology. In 2002, they bought Inktomi, a "behind the scenes" or OEM search engine provider, whose results are shown on other companies' websites and powered Yahoo! in its earlier days. In 2003, they purchased Overture Services, Inc.