Results for the year to December 31 2016 show losses grew to £17.4m from £13.8m last time as turnover ticked-up to £342.2m from £312.3m.
HSS said the losses were down to “a year of investment in a new distribution network structure” and “right-sizing” plan for its branches.
HSS shut 18 under-performing branches during the last quarter of 2016 and seven distribution centres during the year.
A further 37 branches are being closed during the first half of this year.
John Gill, Chief Executive Officer of HSS Hire, said: “2016 was a year of significant operational change and investment for the Group.
“The result is an enhanced operating platform that will enable us to deliver superior fleet availability to customers right across our network, creating the foundation for future sustainable profit growth.
“While we made good progress in key accounts, specialist rental and our fast-growing Services business during the year, this was not matched by revenue growth in our core Rental business and re-establishing momentum in this area is our primary focus in 2017 and beyond.
“Our markets remain competitive on price, but the initiatives implemented over the last 12 months – and the ongoing programme of network optimisation – have strengthened our capabilities and leave the Group well positioned to continue to serve our existing and future customers.”