The extent of any shift in borrower demand toward loans from big banks rather than from niche funders "is not a big wave at the moment, it has been somewhat gradual", Paul Lahiff, managing director of Mortgage Choice said at a media briefing yesterday.Lahiff said that even so, with the move to the major lenders, pressure had been applied to service levels.He added that the Mortgage Choice lending book is growing above system, with the book pushing $31 billion at an unspecified date in 2007, which is five per cent higher than the $29.6 billion at financial year 2007.On the liklihood of increasing mortgage rates (due to higher funding costs) Lahiff commented, "I think everybody is so keen to maintain their mortgage market share that nobody wants to be the first one, although they have all been tempted."The bigger players can handle the pain better than some of the smaller players".Lahiff used the example from the 1990's where Commonwealth Bank was cutting rates. "Everybody was bleeding really badly, but he knew (David Murray) that the bank could handle the bleeding better than most."So I think there is a bit of a war of attrition in it, and a bit of a market share war in it.I guess time will tell".In response to market share, Lahiff said, "In our view the major banks, the regional banks and some of the foreign banks, and probably some of the credit unions will continue to fight pretty hard to win business".