Last month Capital for Colleagues invested in Midland Construction Supplies Ltd, which has depots in Wolverhampton and London.
CSL supplies civil engineering and construction contractors from depots at Penrith, Redruth and Sittingbourne. The loan will be used for working capital purposes.
John Eckersley, CEO of Capital for Colleagues, has a 7.5% stake in CSL, which he acquired in April 2013.
Mr Eckersley said, "With established UK-based operations and a commitment to incorporating employee ownership schemes, Civils Store Ltd represents another compelling investment opportunity. This transaction follows our recent investment in Midland Construction Supplies Ltd in April 2014 and strengthens our highly prospective portfolio, which now includes six companies."