In 1798 David left the company to found the Commercial Bank of Scotland. Between 1805 and 1810 he moved to Edinburgh setting up David George Sandeman & Co at 11 Forth Street in the eastern New Town.[4] In 1810 he founded the Commercial Bank of Scotland, originally housed at 22 Picardy Place at the head of Leith Walk.[5] In 1835, shortly before his death, he was elected a Fellow of the Royal Society of Edinburgh.