Greenmantle | 3,093 followers on LinkedIn. Greenmantle is a macroeconomic and geopolitical advisory firm with offices in New York, London, and San Francisco. | Greenmantle is a macroeconomic and geopolitical advisory firm with offices in New York, London, and San Francisco. We advise a select and strictly limited group of clients in the energy, financial, industrial and technology sectors. We believe that decision-makers today have an acute need for historical perspective.