U.K. fintech start-up Starling Bank – which operates solely on a mobile app – said it plans to raise £40 million ($54 million) from investors to drive expansion into markets beyond the U.K.

The London-based challenger bank doesn’t have a single physical branch, and claims to be the first digital challenger of its kind to offer customers current accounts.

Challenger banks are smaller retail lenders that are set up with the aim of disrupting big, established financial institutions.

Starling was given banking passport rights in neighboring country Ireland in June, in a move seen to mark its first expansion to a European Union country.

Capital raised by the fundraising round will allow the fintech bank to continue its growth across Europe, Starling said.

Its plan to raise the cash follows the bank’s initial fundraising round in January last year, which raised £48 million ($65 million), and was led by American trader Harald McPike.

The start-up claims to be the first fintech challenger bank to offer current accounts, and said the latest investment will bolster its aim to “diversify” this product.

Starling’s Boden added: “This is yet another stepping stone in Starling’s mission to realign the retail banking sector in the interest of consumers. On each occasion I set out to secure further funding, I am reminded of my objective to ensure everybody has an offer of a healthier financial life.”

In August, the CEO told CNBC that Starling was working on multi-currency accounts to push this international focus.

The app-based bank hopes to take advantage of a European Union (EU) regulation which will open up banks’ software infrastructure to third parties.

Proponents of the regulation, who refer to the trend as “open banking,” believe it will offer fairer competition standards for rising stars in the financial services, especially the ever-evolving fintech sector.

Several banks are gearing up to get ready for the new law, set to take effect from January 2018 onwards. Ireland’s Ulster Bank is one of the latest to have unveiled a new application programming interface (API) which will allow fintech developers to build products using banks’ data.

“Starling is one of the first digital bank to enter fast digital payments, we’re the first digital bank to have fully compliant APIs. We have built the organization for a world in which open banking is how people do business,” Boden told CNBC last month in an interview.

The firm launched its Marketplace, a concept which allows third-parties to add their products to an ecosystem accessible via the Starling’ app, earlier this month. The Starling app is currently available on both Google Play and the Apple Store.