In 1802, she applied to the city authorities for a permit to trade as a månglare.
The månglare-permit was granted by the city authorities to people (foremost married women) who could argue that they needed to support themselves, and there where regulations to prevent a månglare from expanding their business beyond what was needed for self support.
Maria Boberg belonged to the minority of månglare who managed to become wealthy on her business.
A sign of this was the fact that Maria Boberg was not addressed with the title månglare (which was her official and formal profession), but as a fruit merchant.
She left her business to her niece and foster daughter Charlotta Christina Boberg.