European mPOS provider SumUp has landed a new round of funding. Though the exact amount was not disclosed, the company said a "double-digit million euro" investment included Groupon, American Express and existing investors.

SumUp said the new funds will be used to support continued expansion into new territories and to build out its end-to-end payment solution. The company said funds will go towards product development as well.

"We are delighted to bring on Groupon and American Express as financial investors," said SumUp CEO Daniel Klein. "Both companies share our vision and our commitment to empowering small businesses."

With the new funds, Klein said SumUp is better equipped to execute on its vision of helping make small businesses more successful by simplifying payments, reinventing the point-of-sale experience, and ultimately helping enhance merchant-customer relationships.

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