Keep an eye on Affirm Holdings (AFRM), we noted on August 2.

At the time, the stock traded around $63 a share.

All after Square announced it was buying its competitor Afterpay in an all-stock transaction worth $29 billion. And all as “buy now, pay later (BNPL)” just begins to gain popularity.

In fact, according to Barron’s, “BNPL is gaining popularity given that interest rates are ultralow, reducing costs for consumers. Other fintech apps have entered the market, including Affirm, a pure play on the sector, and PayPal (PYPL). Apple (AAPL) is also developing a BNPL service with Goldman Sachs Group (GS), its credit-card partner.”

In the first two months of the new year, BNPL saw 215% year over year growth, as noted by Adobe. Even better, according to Bank of America, BNPL apps could grow 10-15x by 2025, and could eventually process $650 billion to $1 trillion in transactions. In addition, according to Yahoo Finance, “The trend is also part of a generational shift: The average user of buy now, pay later services is their 30s, BofA found, and the average amount spent was around $200 to $500 (as compared to $5,000 to $6,000 one would spend on a credit card).”

Today, AFRM is up to $100.20 a share.

All after AFRM entered into a partnership with Amazon.com.

According to Investor’s Business Daily, “Affirm said after the market close on Friday that Amazon is testing Affirm’s system of buy now, pay later — also known as BNPL installment payment plans — with some customers. The e-commerce giant plans to make Affirm’s BNPL services more broadly available in the coming months.”

If you took the trade on August 2, you’re up just over $37 a share.