Stripe, a US fintech firm founded by two brothers from Limerick, is now valued at more than $9 billion after having raised $150 million in an investment round. The Silicon Valley company has nearly doubled its valuation since July 2015, when a funding round then increased the company’s value to $5 billion.

The Business Insider reports that the investment round was led by CapitalG and General Catalyst, and included participation from existing investors including Sequoia Capital. Facebook investor Peter Thiel and Tesla founder Elon Musk have invested in the company in previous rounds.

The online payment company was founded in 2011 by Patrick and John Collison. Stripe, whose software allows businesses to accept and track digital payments, now has users in 110 countries.

Business is booming in the US for #fintech start-up @stripe

— SiliconRepublic (@siliconrepublic) November 25, 2016

Stipe’s payments platform has been increasingly popular with startups like Kickstarter, but now larger companies, including Adidas, SAP, Macy’s and Slack, are becoming customers.

The latest funding round makes Stripe one of the biggest new technology companies in the United States.

According to a source close to the company, Stripe intends to use the money to expand internationally, build more tools for business customers, and invest in or acquire other companies.