Two of the most intriguing stories in tech this week include the impressive success of Square's (NYSE:SQ) Cash App -- a peer-to-peer payment service -- and chipmaker NVIDIA's (NASDAQ:NVDA) earnings. Headlines for both companies sent their stocks in opposite directions.

Here's what investors should know.

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Square's relentless rise

Shares of the financial-technology company have been on a tear -- and last week's gains for the stock to record highs, after an analyst upgraded the stock, extended Square stock's impressive run even further.

Square's fast-growing peer-to-peer payment app, Cash App, saw its cumulative downloads rise to 33.5 million in July, exceeding PayPal Holdings-owned Venmo's 32.9 million downloads, according to marketing intelligence company Sensor Tower and the equity research team at Nomura Instinet. 

"If the Cash App continues to grow rapidly, the business could reach or even exceed $100 million in sales by 2020, even without deeper active user penetration," said Nomura Instinet analyst Dolev (via CNBC). On the heels of this development and Square's strong second quarter, Dolev increased his revenue estimates for the company and boosted his 12-month price target for the stock to $86 -- well above the stock's closing price of $72.90 on Friday.

Shares of Square ended the week up about 3%, bringing the stock's year-to-date return to 110%.

NVIDIA's pullback

Shares of NVIDIA pulled back this week, falling about 4%. The stock's decline came despite better-than-expected revenue and adjusted earnings per share for its second quarter of fiscal 2019.

NVIDIA reported revenue of $3.12 billion, up 40% from $2.23 billion in the year-ago quarter. Net income increased even faster, thanks to a 490-basis-point increase in the company's gross margin. Net income was $1.1 billion, up 89% year over year. That translates to adjusted earnings per share of $1.76. 

On average, analysts expected revenue and adjusted earnings per share of $3.10 billion and $1.66, respectively. 

Where the chipmaker may have spooked investors was with its revenue guidance. Management said it expected third-quarter revenue of $3.25 billion, "plus or minus 2%." On average, analysts were expecting third-quarter revenue of $3.34 billion. Part of NVIDIA's weaker-than-expected guidance can be attributed to the company's anemic outlook for cryptocurrency-specific products.

"Whereas we had previously anticipated cryptocurrency to be meaningful for the year, we are now projecting no contributions going forward," management said in the prepared remarks for its earnings call." This warning came after the company crypto-specific product revenue in its second quarter was just $18 million -- far below the $100 million it had expected.

Daniel Sparks owns shares of Square. The Motley Fool owns shares of and recommends Nvidia and Square. The Motley Fool has the following options: short September 2018 $80 calls on Square. The Motley Fool has a disclosure policy.