Changes to fixed mortgage rates by a number of lenders over the past two weeks have been characterised as evidence of a new home loan war by several commentaries. Among the latest changes, Westpac has cut its two-year rate from 5.59 per cent to 4.99 per cent and its five-year rate from 5.89 per cent to 5.69 per cent. The cuts apply to customers on the Premier Advantage Package.Aussie Home Loans has cut its three, four and five-year rates by up to 10 basis points. Its three-year rate is now 5.29 per cent.CUA has cut its three-year rate to 5.3 per cent. Rams Home Loans, Newcastle Permanent and National Australia Bank have also cut their fixed rates in the past week.However, lenders change their fixed rates all the time and the idea that there is a war on is a stretch. Data supplied by Infochoice show that about 50 lenders have changed their three-year fixed mortgage rates since November. These rates bounce around because they are priced with reference to interest rate swaps, not the Reserve Bank cash rate, and these swaps are priced in the capital market on a daily basis.According to Infochoice, one-year fixed mortgage rates have fallen by an average of 17 basis points since the beginning of November. Three-year fixed rates have fallen by an average of 14 basis points over the same period, and five-year rates have fallen by an average of 14 bps.The average one-year rate is now 5.47 per cent, according to Infochoice, and the lowest rate on the market is 4.98 per cent.The average three-year rate is 5.48 per cent, with the lowest rate being 5.09 per cent (Rate City puts the three-year average rate at 5.53 per cent and the Reserve Bank puts it at 5.5 per cent).And the average five-year rate is 6.01 per cent, with the lowest rate being 5.69 per cent.The average standard variable rate for the lenders in Infochoice's database is 6.07 per cent, with the cheapest rate standing at 5.09 per cent. Rate City puts the average rate at 5.97 per cent.According to the Reserve Bank, the average standard variable rate offered by a bank is 6.45 per cent. Applying an average discount of 75 basis points, the RBA puts the average discounted variable rate at 5.7 per cent.The average standard variable rate offered by a mortgage manager is 6.05 per cent, according to the RBA, and the average basic mortgage manager loan rate is 5.4 per cent.What these numbers suggest is that borrowers looking for a cheap rate do not have to lock in for two or three years, as some lenders have suggested in their marketing material. The cheapest standard variable rate on the market is about the same as the best three-year rate on offer.What is interesting is that while fixed mortgage rates have been falling over the past few months, the capital market yields that drive these rates have been rising. Three-year Australian government bond yields have gone up by about 25