The company told ZDNet Australia Lindsay left to pursue some of his own business ideas.
Aussie claims to be Australia's largest non-bank lender, and is understood to utilise Microsoft technology extensively in its IT operations.
In mid-2004, Next reported that Aussie outsourced management of its storage needs to Optus, where Lindsay said he could draw on the carrier's storage area network.
Aussie is also known to have a significant partnership with niche software developer Simbient, which develops some of Aussie's lending applications.