Glasgow-based Fleet Alliance saw its fleet size rise to 18,400 vehicles, after a fifth successive year of growth.
The fleet lessor said it has experienced continued growth in the SME and mid-corporate sectors of the fleet and business market.
At the same time, the company reported a fifth successive year of record income levels and operating profit performance.
Fleet Alliance also revealed a number of new technological enhancements to its cloud-based e-Fleet fleet management system.
Through these changes, drivers will be able to record business and private mileages remotely and electronically, and mileages can be verified using national postcodes.
Drivers will also be able to compare and contrast vehicles online, trade up or down – depending on company policy – and place vehicle orders online, as well as having access to specific documents such as insurance certificates or driver licences while mobile.
Fleet Alliance managing director, Martin Brown said: "Looking at the coming year, ‘cautiously optimistic’ would perhaps best sum up our mood. With profit warnings in the UK, a slowing Chinese economy and turbulence in global markets, it would appear that some of the signals are pointing to this year being a little tougher than 2015.
"However, we remain confident that 2016 will still prove to be a strong year for the fleet and leasing sector in the UK. And we go into the year looking to build on our fifth successive record performance, although the level of growth is more difficult to predict at this stage."