The early development of ISS mirrors the early development of the Inchcape Group which traces its origins back to 1847 when two Scotsmen met in Calcutta. William Mackinnon and Robert Mackenzie, two merchants from Campbeltown, formed a general merchanting partnership, Mackinnon Mackenzie & Company (MMC).
Realizing the benefits of combining trading with ocean transport, the business expanded and diversified. In 1856, Mackinnon at age 34, founded the Calcutta & Burmah Steam Navigation Company (C&B) and secured from the East India Company the contract for carrying the mails between Calcutta and Rangoon. Further, he incorporated the company in London with a capital of £35,000, of which MMC invested £7,000, becoming agents for the new shipping line.