National Australia Bank's decision to pass on to home loan borrowers only 20 basis points of the Reserve Bank's 25 basis point cash rate reduction does not come as much of a surprise.At last week's results briefing, NAB's executive director finance, Mark Joiner, said it was unlikely that the bank would seek to continue growing its mortgage book at twice system, as it did over the past year.Joiner said: "We would expect pressure on net interest margins going forward. Wholesale funding costs are higher and we also have heightened competition for assets in Australia. "On the mortgage flows, we don't necessarily expect business to keep going at this multiple of system."NAB kept the home loan sales flowing through 2012 by pitching its standard variable rate at around 10 basis points below that of its major bank rivals.ANZ joined Commonwealth Bank and Westpac yesterday when it announced that it would cut its variable mortgage rate by 25 basis points.The state of play among the Big Four is that NAB's standard variable rate will fall to 7.47 per cent, ANZ's to 7.55 per cent, CBA's to 7.56 per cent and Westpac's to 7.61 per cent.NAB is positioning itself for continued mortgage growth, but not at the same rate as over the past year.The risk it runs is that negative consumer sentiment will muck up its plans. This time last year Commonwealth Bank added 20 basis points to the 25 basis point increase in the cash rate and, as a result, its customer satisfaction scores plunged and its slowdown in mortgage sales was much greater than the bank had anticipated.A number of other lenders announced interest rate changes yesterday. ING Direct, Suncorp, Bankwest, AMP Bank, Gateway Credit Union and Teachers Credit Union all announced that they would reduce rates on their variable rate home loans by 25 basis points, effective within the next week or two.ING Direct's Mortgage Simplifier rate falls to 6.87 per cent.AMP's standard variable rate falls to 7.57 per cent and its Essential Home Loan rate falls to 6.6 per cent.Bankwest's standard variable rate will fall to 7.45 per cent.Suncorp cut its standard variable rate on home loans from 7.83 per cent to 7.58 per cent. It is maintaining its 103 basis point discount for customers who take the Suncorp "Bank My Home" package, offering a package rate of 6.55 per cent.Rabobank will reduce all variable base rates on its rural loans by 25 basis points, effective from November 18.Mortgage aggregator AFG reported that the home loan market is getting more competitive, with smaller lenders increasing their share.AFG said that 21.1 per cent of the loans written by its brokers in October went to "non-major" lenders. This is the highest share small lenders have enjoyed for several years. Volumes were down in October, with AFG brokers writing 6349 loans, compared with 6687 in September and 7198 in August - the peak month for the year so far.