Turquoise International is a United Kingdom investment firm that makes venture capital investments and also provides merchant-banking / corporate-finance advisory services within the energy, environment, and efficiency (''cleantech'' / ''energy-transition'') sectors. The firm was founded by Managing Director Ian Thomas and partners, and operates as one of the longer-established UK dedicated cleantech / energy-transition investment and advisory boutiques, providing both principal-investment capital deployment and specialist M&A and capital-raising advisory services to clean-energy, energy-efficiency, renewable-energy, environmental-services, and adjacent sustainability-sector companies. The firm is based in London, United Kingdom. Detailed current aggregate AUM, fund-vintage disclosures, and comprehensive transaction-advisory track-record are partially documented in mainstream UK cleantech / energy-transition industry databases. The row should be noted as Active.