Portman has made a number of changes to its fixed rate mortgage range following the recent rise in swap rates.
The society is now offering a two-year fixed rate of 4.83%, or 5.59% with no arrangement fees.
Its three-year fixed rate is now at 5.25% or 5.49% with no arrangement fees.
It is also offering a three-year fixed rate at 5.25% with a £499 arrangement fee, and at 5.09% with an arrangement fee of £599.
Portman is also offering a five-year fixed rate at 5.15% with a £599 arrangement fee, or 5.29% with an arrangement fee of £499.
It is also offering a five-year fixed rate at 5.25% or at 5.39% with no arrangement fee.