Banco Santander, the largest bank in Europe by market capitalisation, is to invest 5m ($6.6m) into Swedish mobile payments company iZettle.
The venture aims to enable merchants throughout Europe to accept credit card payments on smartphones and tablets, beginning with a partnership between iZettle UK and Santander UK.
Ramón Tellaeche, head of Santander Cards at Banco Santander, said: "Millions of small business owners and professionals in the markets where we operate need an alternative to conventional credit card terminals, and simple software to manage and analyse their transactions."
Merchants who use the solution pay a percentage (2.75%) of each transaction made, instead of a subscription, set up fee or monthly fee.
Jacob de Geer, co-founder and chief executive of iZettle, said: "We want to bring iZettle to the world, and to do that we must have strategic partnerships with the world’s leading banks."
"Our relationship with Banco Santander is central to our transition from local to multinational services."
The iZettle app for accepting credit card payments can be downloaded for free from the Apple Store or Google Play in the UK, Spain, Germany, Sweden, Denmark, Norway and Finland.
Its Chip & PIN and Chip & Signature card readers can be purchased from the iZettle website.