"This is really significant for Klarna," David Sykes, Klarna's chief commercial officer, told CNBC, adding the company has already doubled the number of new merchants in the three months since it began implementing the new integration with Stripe in October.

"We added 100,000 new merchants in 2024 and we are already seeing that growth rate increase with this agreement." he added.

Analysts recently valued Klarna, which was founded in 2005, in the $15 billion range. At its peak during the pandemic-led surge in fintech stocks, the company attracted a valuation of $46 billion in a funding round led by SoftBank's Vision Fund 2 back in 2021.