The company, known for its yellow-coloured storage sites, reported an adjusted pre-tax profit of £29.2m in the year to 31 March compared with £25.5m the previous year.
Sales were up four per cent to £72.2m, while its net asset value rose seven per cent to 446.5p per share.
The group, which is focused on London and the south east, owns 77 stores including 10 Armadillo Self Storage stores, which it bought through a joint venture in April.
It is also working on new stores in Enfield, Guildford and Manchester.
“In an improving economy, we have delivered occupancy, revenue and cash flow growth for the fifth year in a row following the deep recession in 2008 and 2009,” chairman Nicholas Vetch said.
“Land in London and the south east continues to be increasingly scarce for non-residential development which should benefit Big Yellow as new supply of self storage facilities will remain constrained,” Vetch added.
However, he warned that political events such as next year’s general election could create uncertainty in the market, echoing comments made by property firms Land Securities and British Land.