National Australia Bank yesterday received clearance from the ACCC to buy the mortgage management business of Challenger as well as the three mortgage aggregation platforms, which service brokers, under its control.The bank will also buy a portfolio of $4 billion in home loans from Challenger.NAB thus avoided the need to sell one of those three aggregation platforms (as suggested in recent industry talk) and obviously overcame earlier industry chatter that the ACCC was leaning toward blocking the takeover.The ACCC said in a media release that it concluded that the takeover "was unlikely to substantially lessen competition in the market for the supply of home loans."The ACCC said in the release that its "market inquiries revealed that NAB's proposed acquisition of the Challenger mortgage portfolio will only increase its share of the Australian home loan market by less than one per cent" which must relate to the  acquired pool of loans, and not to the benefit, if any, of owning several platforms in the broker channel where NAB historically has sourced few loans.The commission also said that it estimated that the three broker platforms - Choice, PLAN and FAST - "have a combination of exclusive and non-exclusive relationships with approximately 40 per cent of brokers nationally."The ACCC noted that brokers have the ability to switch to alternative broker distribution platforms.