Macquarie Group is looking for new markets in asset finance to fill out a portfolio that already includes, motor vehicles, rail, aircraft, helicopters, technology and energy and mining equipment.The co-head of the group's corporate and asset finance division, Garry Farrell, said the group had a very consistent approach to looking for opportunities."We look for big markets and then look for niches within those markets. We like scale and we like to see capex in those markets growing each year," he said.Macquarie's asset finance book has grown from A$12.6 billion in 2011 to $29.6 billion at the end of last year.Over the period it has acquired two vehicle finance business - the Esanda dealer finance portfolio from ANZ and Advantage in the United Kingdom. It acquired Euro Rail in 2013 and a portfolio of mining equipment assets in 2012.In March last year Macquarie paid US$4 billion to acquire an aircraft operating lease portfolio from AWAS Aviation Capital. The portfolio was made up of 90 aircraft leased to 40 airlines.Macquarie has 217 aircraft in its fleet, leased by 94 airlines.Speaking at an investor briefing yesterday, Farrell said the business was expanding into funding renewable energy assets and mobile telephony. It is hoping to take advantage of adverse conditions in the resources sector.