Square has received a new investment from Visa, which is the largest credit card company in the world. While the exact amount of the investment is unknown, it’s rumored to be in the millions.

Square COO Keith Rabbois told the Wall Street Journal that the company will continue to “explore collaborative partnerships that might make sense,” that the two companies’ visions “align”. The journal reports:

More than eight million U.S. businesses accept Visa and Mastercard, Rabois said. Square is trying to help the 27 million businesses and entrepreneurs that don’t accept credit cards because they haven’t qualified due to poor or no credit history, Rabois said.

The investment comes at a very interesting time in Square’s existence. The company is certainly really starting to build steam, but as you may know, Square co-founder Jack Dorsey recently returned to day-to-day operations at Twitter, in addition to remaining in the CEO role at Square. The man has his hands full, no doubt. He’s essentially taken Evan Williams’ place at Twitter, and Square continues to grow its staff.

Interestingly enough, Rabbois told the WSJ that he interacts with Dorsey the same amount that he did before Dorsey went back to Twitter. It doesn’t sound like the Twitter gig is putting too much of a strain on Square.

The backing of Visa should alleviate any of the concerns out there about Square’s potential for success, and about security, for that matter. You may recall earlier this year when Square competitor Verifone blasted Square over a security issue. The claims ended up being blasted themselves, and essentially called out as being a back-handed competitive stroke.

Now, you have to wonder if investments from other major credit card companies will follow.