Niels Onstad together with his brother Haakon Onstad, he started the shipping company, Niels Onstad Tank Rederi A / S, which later was named Niels Onstads Tankrederi with headquarters in Oslo. Haakon Onstad had entered ship owning in 1932 with the Pan Gothia but because of the uncertain financial times the ship was given Swedish registry under Rederi A/B Pagota. In 1940, Niels Onstad fled to the United States during the Occupation of Norway by Nazi Germany. Haakon Onstad relocated to Kungsbacka, Sweden where he formed Rederi A/B Kungsoil and Rederi A/B Monacus.
Non-cemetery burial on hilltop overlooking the Henie-Onstad Museum