As suggested, most likely a Th. Olsens Eftf. mark - after Theodor Olsen died in 1890, his widow sold the business to brothers Magnus and Knut Aase in 1903/04, from the firm's founding in 1868 until 1903, their marks were initials and/or names (M&T OLSEN, Th.O, Th.Olsen, Theodor Olsen), but from 1904 they used Magnus Aase's conjoined AM-over-7-dots (for the 7 hills/mountains of Bergen) mark, Aase had used it in his workshop from its founding in 1899 until 1903, both as retailer and for his shop's production. Magnus Aase's business continued, primarily as a retailer, using the marks 'M.AA.' or 'M.AASE' until closing in the '90s, their equipment was sold to Th. Olsens Eftf. around 1925-30. Th. Olsens remained in the hands of the Aase family for well over a century, the mark changed with time, to a variety of pointier crown-like 'AM' over the 7 dots, and even after Lilli-Anne Alver acquired the company, changing the name to 'Arven AS' in 2016, they continue to use a stylized variant of the mark, a pointy crown-like 'AM' without the dots.
~Cheryl