Major bank ANZ has come out on top of AFG's panel competitors in October by garnering the largest market share gains among the group's 1800 brokers.
In AFG's first Competition Index - measuring market share movements among the aggregator's panel lenders - ANZ rose to 20.1% of all loans processed, up from 15% in April 2011, or a 34% increase.
AFG's figures showed that Westpac dominated the investor sector, where its brands secured a 29.2% loan share ahead of rivals CBA (24.5%), ANZ (17.1%) and NAB (12.6%).
Commonwealth Bank maintained overall dominance through AFG with a 25.9% market share, benefiting from particular strength in the First Home Buyers market.
Meanwhile, Suncrop was the largest of AFG's non-major lenders, with an overall loan share of 5.1%.
AFG general manager of sales and operations Mark Hewitt said ANZ's competitive professional package and fixed rates "are doing well for them" in a more competitive mortgage market generally.
"Suncorp have adapted their deposit requirements to assist first home buyers, in particular construction loans, and the results speak for themselves," Hewitt added.
First homebuyers flood back to market