While Macquarie Group is easily the best-performed large-cap banking stock on the ASX this year, a little-known financial services company with a bank in Papua New Guinea has trumped the Millionaires' Factory.Shares in Port Moresby-based Kina Securities have soared 40 per cent since the end of December(Macquarie up 30 per cent), as Australian institutional investors such as Perpetual Trustees have begun buying into the company's growth story.Although Kina is a diversified financial services player with an active presence in PNG's funds management and stockbroking sectors, the group's retail bank has emerged as an important driver of the company's profitability.Kina Bank is PNG's fourth largest retail bank with around 13,000 customers, mostly in Port Moresby and other urban centres of the country.It has a modest distribution network comprising no eftpos machines, ten automatic tellers and six branches.However, two big strategic developments are about to transform Kina Bank's role in the PNG banking market.The first is the recently announced acquisition of ANZ's retail banking operation in the country.The transaction will double Kina's deposit book to more than 2.3 billion Kina (A$1 billion) and boost its loan base by around 50 per cent to 1.4 billion Kina (A$600 million).Its share of the national deposits market will climb to just under ten per cent.The acquisition will also deliver distribution grunt to the bank: ANZ will transfer 2000 eftpos machines, 15 branches and 80 ATMS. The second factor driving investor interest in the banking neophyte is its big capital spending on digital platforms.Kina Bank is leading the PNG market in the provision of digital financial services, especially in mobile transaction banking. As a relative newcomer, the bank is not saddled with legacy banking platforms that so often delay the entry of entrenched incumbents into emerging sales channels."That's one of the big positives - we don't have a legacy platform problem," says chief executive, Greg Pawson."We recently upgraded our core banking infrastructure to InfoPro - a Malaysian developed platform."It's clean infrastructure although we do have to expand the build to accommodate online credit card transactions."Pawson joined Kina Bank earlier this year after almost two decades at Westpac, most recently as head of the Sydney bank's South Pacific banking unit.In that role he led the program, which saw Westpac divest most of its banking assets in the region, including Vanuatu, Tonga and the Solomon Islands.Pawson believes the Australian banks are exiting the Pacific because of operational challenges and the sovereign risks they present."They're difficult businesses to run," he says."Transaction volumes take on a different character in a developing market - forty per cent of transactions relate to migrant remittances."Pawson acknowledges that the company has plenty riding on integrating the ANZ operations and customers successfully.In the weeks since the sale was announced in June, PNG newspapers have carried several stories highlighting customers' concerns about ANZ's exit.Some of the concerns related to misplaced perceptions in PNG that Kina Bank was effectively a Malaysian-owned institution.That might have been the case in the past, but PNG's central bank recently forced a