The early prosperity of the town is largely due to the nearby quarries of slate, whose abundant use for the roofs of Angers led to the city's nickname, the "Black City" (or "La ville noire", in French). As of 1911, existing industries noted in the Encyclopædia Britannica for that year included the distillation of liqueurs from fruit (Cointreau, a brand of triple sec orange liqueur, is produced to this day in Saint-Barthélemy-d'Anjou, a commune in Angers urban area); cable, rope, and thread-making; the manufacture of boots, shoes, umbrellas, and parasols; weaving of sail-cloth and fabrics; machine construction; wire-drawing; and the manufacture of sparkling wines and preserved fruits. The chief articles of commerce, besides slate and manufactured goods, were hemp, early vegetables, fruit, flowers, and live-stock.
Many of these industries present in 1911 have since disappeared, though Cointreau continues to produce liqueur. Other contemporary industries include the manufacturing of lorries (Scania) and computers (Bull, Packard Bell, NEC) as well as research in horticulture and bio technologies. Angers economy is also tributary to the presence of many administrative, educational and health institutions, and is also characterised by a great number of small firms, often oriented towards the agricultural tradition of Maine-et-Loire. Thanks to its several higher education schools, laboratories, and various offices, Angers is the largest horticultural centre in Europe. It is as well a regional finance centre, with many banks and insurance companies having a regional seat there (Afone, CNP Assurances, Crédit agricole, Fiducial, Groupama...).
Angers is an important congress and fair centre. The congress activity gives each year a fallout of eight millions euros to the local commerce and a new congress centre should replace the current one by 2016, doubling this economic fallout. The Parc des Expositions, where fairs are held, welcomes 600,000 visitors and
