Mercedes-AMG GmbH, commonly known as AMG, is the high-performance subsidiary of Daimler AG. AMG independently hires engineers and contracts with manufacturers to customize Mercedes-Benz AMG vehicles. Mercedes-AMG is headquartered in Affalterbach, Baden-Württemberg, Germany.
AMG models typically have more aggressive looks, a higher level of performance, better handling, better stability and more extensive use of carbon fibre than their regular Mercedes-Benz counterparts. AMG models are typically the most expensive and highest-performing variant of each Mercedes-Benz class.
Source: wikipedia