Thorpe, which is based in Redditch, has acquired all of the Walsall firm’s issued share capital.
The Redditch firm employs about 600 people and sells products around the globe. The company announced a four per cent rise in annual revenues last September to £53.4 million.
Portland is a sign lighting specialist that designs and manufactures products to companies including Marks and Spencer and Specsavers.
Andrew Thorpe, chairman of Thorpe, said: ‘We don’t intend to change the business much – it’s already very successful.’