What happened

Block (SQ -1.68%) stock -- the fintech giant that used to be known as Square and that still trades under Square's ticker symbol -- has notched a tidy 4.7% gain as of noon ET Tuesday.

Two sizable pieces of news are driving the stock's price gains.

Man lines up wooden blocks that read PRICE and a green arrow.

Image source: Getty Images.

So what

In the first bit of news, Block announced after close of trading yesterday that it has completed its acquisition of buy now, pay later (BNPL) company Afterpay and also launched Square's "first integration with Afterpay" functionality, such that "sellers using Square Online for e-commerce in the United States and Australia" can now offer buyers the ability to buy now and pay in installments.    

In making its announcement, Block quoted one of its customers praising its success using Afterpay, exulting that "our purchases are nearly 20% larger when shoppers use Afterpay" -- a trend that, if it holds true across other users, should provide a revenue boost not only to Block's customers but to Block itself as it takes its cut of revenue.

Now what

Block noted further that "BNPL service" is growing fastest among the company's most desirable segments -- young "Gen-Z and Millennials, [who] comprise 75% of BNPL users," and who Block presumably hopes will continue using BNPL payments over the rest of their (longer than older customers') lives.

Does that sound as if it might boost Block's growth prospects just a bit? I think so. And it seems I'm not alone, because in the second bit of news that's driving Block stock higher today, we just learned that growth stock fan Cathie Wood bought more than 105,000 shares of Square yesterday, in three installments valued at roughly $13 million in total.  

It's a sizable buy for the tech guru -- about 0.5% of all her funds' assets invested in a single day -- and investors are taking Wood's purchase as an endorsement and buying some Block shares of their own.