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Stripe, the online payments company that has essentially become the default acceptance service for startup companies in the U.S., has raised around $150 million in a new round of funding. The round values the company at $9.2 billion after the cash infusion, up from $5 billion last year.

Alphabet’s late-stage investment arm, CapitalG (formerly Google Capital), co-led the round along with existing Stripe investor General Catalyst. Stripe has now raised more than $400 million in venture capital.

Stripe makes software that developers use to quickly start accepting credit card payments and other digital payments on their websites and apps. The company, run by brothers Patrick and John Collison, competes against PayPal-owned Braintree and other older services.

The $9 billion valuation has to leave some people scratching their heads at Square, the publicly-traded payments company with a market cap of $4.4 billion. Both companies make money by taking a cut of each card payment a merchant accepts, though Square’s business is predominately at brick-and-mortar merchants while Stripe’s is online.

Square’s payment volume is larger than Stripe’s currently, but Stripe is nearing Square’s volume and growing faster, according to a person familiar with this latest investment. Stripe also has a much smaller workforce than Square — about 550 employees compared to more than 1,000.

On the flip side, Square is more diversified, generating revenue from non-payment products such as its Square Capital lending business and Caviar restaurant-delivery operation.

A Stripe spokesperson confirmed the funding round but declined to comment on business figures. The Wall Street Journal first reported the news.