The H-1B is a visa in the United States under the Immigration and Nationality Act, section 101 , that allows U.S. employers to employ foreign workers in specialty occupations. A specialty occupation requires the application of specialized knowledge and a bachelor's degree or the equivalent of work experience. The duration of stay is three years, extendable to six years, after which the visa holder can reapply. Laws limit the number of H-1B visas that are issued each year. There exist congressionally mandated caps limiting the number of H-1B visas that can be issued each fiscal year, which is 65,000 visas, and an additional 20,000 set aside for those graduating with master's degrees or higher from a U.S. college or university. An employer must sponsor individuals for the visa. USCIS estimates there are 583,420 foreign nationals on H-1B visas as of September 30, 2019. The number of issued H-1B visas have quadrupled since the first year these visas were issued in 1991. There were 206,002 initial and continuing H-1B visas issued in 2022.