Tim Wildash, the chief executive of ATM operator Customers Limited, left the firm yesterday. He had given notice to the board of his intention to leave in recent weeks.Peter Polson, the chair of the board of Customers, said: "Tim decided he wanted to move on and do other things. That's fine."Wildash founded ATM Solutions in 2001 at a time when the number of ATMs in Australia was one third its present level.He remained at the helm as ATM Solutions was sold to Bank of Queensland, then to Macquarie Bank, and then sold a third time, in 2007, to Customers. At the time, the latter firm was in the early stages of shifting from being a small cap mining stock to becoming a payments system challenger.Customers now operates the largest fleet of ATMs in Australia and is expanding in New Zealand. It was an early investor in the switch Strategic Payments Services.The ASX-listed firm has a market capitalisation of A$108 million, about a third of its peak valuation in 2010.