Misys - which provides software to the likes of Lloyds Banking Group, Barclays and HSBC as well as lenders worldwide - is planning to list in early November, just four years after it was taken private by Vista Equity Partners in a £1.3bn deal.
The group is hoping initially to raise around £500m and it is thought the group could be valued as high as £5.5bn when it floats.
Chief executive Nadeem Syed said the timing was right to return to the market, adding that the UK is still "open for business" despite uncertainties over Brexit negotiations.
Misys is headquartered in the UK, but has around 2,000 customers worldwide.
Its IPO adds to a growing list of flotations in recent months as firms capitalise on the strength of the equity markets since the Brexit vote, with the FTSE 100 Index this week smashing through the 7000 mark for the first time since mid-2015.
Price comparison site GoCompare, waste management group Biffa, fitness chain PureGym and Hollywood Bowl have all confirmed plans to list.
Syed told the Press Association Brexit was "not expected to be a factor for us" and London would remain a "substantial hub from a financial services perspective".
He added: "We provide mission critical solutions to our customers and Brexit doesn't change the need to adapt to regulation and serve our customers better.
"This is our back yard and we believe the UK is still open for business."
The firm's IPO comes after a major transformation since its buy-out in 2012, when the group was merged with Turaz, the former treasury and risk management software division of media group and financial information provider Thomson Reuters.
Syed, who joined Misys in 2012 to lead the overhaul, said the group is now nearly three times as profitable.
He said: "I believe that the return to public markets as a larger, more innovative and more effective company is a logical step in our evolution."
The company, which has more than 4,600 employees, traces its roots back to 1979 when it was founded as a computer systems supplier to UK insurance brokers.
Its product range includes software to create consumer banking apps and products for analysing banks' capital management to ensure they comply with regulations.