Big Yellow Group's like-for-like revenues in its seasonally weaker third quarter rose by 8% to £29.6m.
The 73 stores decreased in occupancy by 170,000 sq ft (3.7% of the maximum lettable area at 31 Dec) compared to a loss of 137,000 sq ft in the corresponding quarter last year (3.0% of the MLA at 31 Dec 2016).
Sq ft moved in for the quarter increased by 3% compared to the corresponding quarter last year, while move-outs were up 5% following the strong summer trading.
The group saw continued improvement in net rents over the quarter.
The average achieved net rent per sq ft for the quarter was up 1.3% compared to the corresponding quarter last year.
Closing net achieved rent per sq ft was £26.89, an increase of 2.1% from the same time last year and up 3.3% from 31 March 2017.
Chief executive James Gibson said: 'Following strong summer trading the December quarter, as expected, saw seasonal attrition in occupancy, closing at 80.1%, an increase of 4.6 ppts from the same time last year.
'Given the higher levels of overall occupancy in the business, we are pleased to have seen continued improvement in net rents driven by our pricing model.
'We are also reporting improving growth in year on year revenue over the quarter, with an increase to 8.0% from 5.7% growth reported at the half year.
'Importantly, although this was driven mainly through occupancy, we did see a contribution from an improvement in average net achieved rents.
'We remain focussed on occupancy, January has started positively, and we look forward to delivering growth in occupancy and revenue over the current fourth quarter and continuing this into our seasonally stronger spring and summer trading period.'