Merchant services specialist Tyro Payments has begun clearing a path to a stockmarket listing in a move that could raise at least A$500 million for its current owners.Tyro chairman Kerry Roxburgh yesterday told the company's shareholders in a letter that his board had decided to pursue an IPO of the business as a way to enhance the liquidity of the company's scrip.He revealed that the board had contacted several investment banks to seek advice on the prospect of selling the business through an IPO in the next 18 months.Chief executive Robbie Cooke confirmed the move in an interview with Banking Day."Tyro is considering an ASX listing," he said."We've notified a number of investment banks to indicate to us how we might do that and they will be invited to put proposals forward."Tyro is the country's fifth largest merchant acquirer behind the four major banks.In the 12 months to the end of June 2018 Tyro processed more than $14 billion of over-the-counter payments.Its business strategy is focused on building merchant relationships in the health, hospitality and retail sectors.According to the ASIC database, the business has around 440 million shares on issue that are held by 450  domestic and offshore investors.Parcels of the company's shares are sometimes traded on the Primary Markets online platform where the scrip has been valued at between $A1.25 and 90 cents.That indicates the IPO could fetch the bank's existing owners between $400 million and $550 million.ASIC records show that the paid up capital is $142 million.While merchant payments is Tyro's core focus, the company holds a full banking licence that allows it to market a fee-free deposit product to small businesses.The bank, which has been operating as a merchant acquirer for more than a decade, grew its revenue line by 23 per cent to $148.6 million last year.One of the keys to Tyro's recent surge in customer numbers has been its impressive record of bringing new services to merchants more swiftly than the major banks.Tyro introduced least cost routing of contactless payments in February 2018 - more than a year before Westpac and ANZ launched their offers.Cooke said the early push into least cost routing had been a driver of customer growth last year, which saw the merchant  terminal fleet expand by 5000 or 27 per cent to 23,000."Least cost routing has played a role in customer acquisition since our launch because there is heightened awareness among merchants of the benefits," he said."It is generating cost savings for our merchants so it has also been great for customer retention."The prospect of an IPO could tease out a trade buyer for the business.Several US-based payments companies have entered the Australian market over the last 12 months, including global player World Pay.New York-listed World Pay is a small merchant acquirer in Australia but is seeking to widen its presence by expanding direct links with large and small merchants.World Pay's war chest is set to expand in the next few months after global regulators are expected to approve its planned