KPMG is one of the largest professional services networks in the world and one of the Big Four auditors, along with Deloitte, Ernst & Young (EY) and PwC. Its global headquarters is located in Amstelveen, Netherlands.

KPMG employs 145,000 people and has three lines of services: audit, tax, and advisory. Its advisory services are further divided into three service groups - Management Consulting, Risk Consulting, and Transaction & Restructuring.

The firm was established in 1870 when William Barclay Peat formed an accounting firm in London. In 1877 accountancy firm Thomson McLintock opened an office in Glasgow and in 1911 William Barclay Peat & Co. and Marwick Mitchell & Co. merged to form Peat Marwick Mitchell & Co, later known as Peat Marwick.

Meanwhile in 1917 Piet Klijnveld opened his accounting-firm in Amsterdam. Later he merged with Kraayenhof to form Klynveld Kraayenhof & Co.

In 1979 Klynveld Kraayenhof & Co. (Netherlands), Thomson McLintock (United States) and Deutsche Treuhandgesellschaft (Germany) formed KMG (Klynveld Main Goerdeler) as a grouping of independent national practices to create a strong European-based international firm. Then in 1987 KMG and Peat Marwick joined forces in the first mega-merger of large accounting firms and formed a firm called KPMG in the US, and most of the rest of the world, and Peat Marwick McLintock in the UK.