The Bank of Orion was an important financial institution in the 24th century, one of the most highly-secure such institutions within Federation space. It was located on the planet Orion. (TNG - Cold Equations novel: Silent Weapons)
In 2384, the Bank of Orion hosted a summit between Federation President Nanietta Bacco and Gorn Imperator Sozzerozs. A significant portion of Emil Vaslovik's fortune was held by the Bank, as well. (TNG - Cold Equations novel: Silent Weapons)
Mayereen Viray had an account with the Bank of Orion. (DS9 novel: Sacraments of Fire)