Small mortgage lenders took market share from the big banks last year but have not been able to maintain the momentum in the first quarter of this year.Mortgage aggregator AFG reported yesterday that small lenders' share of loans written by its brokers in March was 25.4 per cent - down from a 12-month high of 27.7 per cent last November.AFG's general manager of sales and operations, Mark Hewitt, said smaller lenders had got back to a more competitive position over the past year but they were struggling to challenge the "overall dominance" of the big banks.Among small mortgage lenders, Macquarie Bank accounted for 6.5 per cent of all mortgages written by AFG brokers in March. Its share has grown from 3.7 per cent a year earlier.Others with significant shares were Suncorp, with 3.9 per cent of AFG's loans in March, ING Direct (three per cent), Bank of Queensland (1.4 per cent), Citibank (1.2 per cent) and AMP Bank (1.2 per cent).Small lenders were strong performers in the fixed rate segment, where they had a 35.2 per cent share in March (although that was down from 42.3 per cent last November). They had a 31.8 per cent share of the refinance segment, a 31.7 per cent share of the first-home buyer segment and a 23.1 per cent share of the investor segment.