E rik Must is a Norwegian self-made billionaire and one of the country's most successful and respected long-term investors. He co-founded the investment firm Fondsfinans in the 1970s and has since built a substantial fortune through his savvy and patient investments in the Norwegian stock market. His primary investment vehicle is his privately owned company, A.S. Mustad & Son.

Must is known for his deep, value-oriented approach to investing, taking significant, long-term stakes in a portfolio of Norwegian industrial, media, and consumer goods companies. He is a major shareholder in the media group Amedia and the industrial conglomerate Borregaard. Unlike many modern financiers, his success is not based on high-frequency trading or leveraged buyouts, but on a classic, fundamental approach to stock picking. He is a highly influential but low-profile figure in the Norwegian financial community.