Montt is founded and led by Jon O’Callaghan, a corporate financier who, since the early 1990s, has been intimately involved in countless IPOs, M&A, and financings of mineral assets from around the world. A native of Perth, Western Australia, he has been based in London since the early 2000's and, in 2021, he and his family immigrated to Nigeria to make their home.

Jon focuses on identifying attractive natural resource opportunities that, with the injection of capital and application of an appropriate strategy, technology, and management, are likely to substantially increase in value in the medium term. He has an extensive capital markets network in London and Australia, and nascent network in Nigeria.

A number of stock exchange listed companies that he has been intimately involved with have gone on to become multi-billion dollar companies, including Independence Group (nickel, Australia), Sandfire Resources (copper, Australia), Jubilee Mines (nickel, Australia), and Kimberley Diamond Company (diamonds, Australia), as well as several large, well-capitalised private enterprises including Energy Development Partners (oil, North Sea) and the Zapadnaya Group (gold, Siberia).

Jon is a graduate of Curtin University and a Fellow of the Institute of Chartered Accountants of England and Wales. He has sat on the board of numerous listed and private companies as chairman, managing director, and director.