Richard Hayward Properties, which is based in Castleton near Newport, has sold a 58,293 sq ft warehouse site in Cornwall for £2m.
The property investor completed the disposal of units 11 and 11a at Callywith Gate Industrial Estate in Bodmin to a private investor.
Most of the space is let to the Royal Mail on a 15-year lease, with fixed rental increases, that started in May 2013. The site is also home to gymnastics and trampoline centre, the Callywith Centre.
Property consultancy Powell Lloyd represented Richard Hayward during the transaction.
James Sanders, of Powell Lloyd, said: "This investment sale shows the strong investor demand for this type of product and the improvement within the commercial property investment market across the South West.
"Our client let the units well and with the security of the income from an established tenant such as the Royal Mail, as well as from Callywith Centre, this opportunity appealed to both national and local investors."