In the 12 months to April the company grew its assets under management by £1.2bn, an 84% jump on where it was this time last year.
Liberty SIPP also doubled its client acquisition rate opening 3,618 new SIPPs in the 12 months to April and now administers 11,904.
The Manchester-based company now has £2.64bn of client assets under administration.
The provider offers one product, the Liberty Option SIPP, which was introduced in 2013 and charges no set up fee and an annual management fee of £175 plus VAT.
The firm says much of its new business had come through “a rapidly growing network of partnerships with platforms and adviser recommendation.”
Liberty SIPP now works with 730 financial adviser firms.
The company employs more than 50 staff and grew its pension administration team by a third in the last year.
Matthew Rankine, director of sales and marketing at Liberty SIPP, said: “Liberty’s fastest ever period of growth is both a source of pride and an inspiration for us to do even better.
“Barely a year after we broke through the £1bn of assets under management mark, it took us just 12 months to grow our SIPP book by the same amount again.
“This is a huge achievement but we’re determined to build on the strength that got us here – our reputation for offering a personal, fast and efficient service.
“We’ve invested in both technology and people, allowing us to handle much greater numbers of clients while maintaining the personal touch that makes Liberty distinctive – and which is the reason so many financial advisers now choose to work with us.”