The S&P 500 has gotten more volatile in September due to several factors, including trouble in China involving the country's second-largest real estate developer, a jump in novel coronavirus cases due to the Delta variant, and the stock market's history of underperforming in September.

However, there are certain stocks that have defied the drop in the broader market and soared impressively in September. Ambarella (AMBA 2.75%) and Match Group (MTCH -1.40%) are two such stocks that have shot up this month.

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Let's look at the reasons why investors are buying shares of these two stocks hand-over-fist despite the sell-off.

1. Ambarella's sizzling growth is here to stay

Ambarella released terrific results on Aug. 31 for the second quarter of fiscal 2022 that blew past Wall Street's expectations, and that seems to have supercharged the stock in September. The company's Q2 revenue jumped 58% year over year to $79.3 million, which was better than its guidance and exceeded the $75.7 million consensus estimate. Ambarella's adjusted earnings came in at $0.35 per share, substantially exceeding the prior-year period's figure of $0.06 per share and analysts' estimate of $0.25 per share.

Ambarella's terrific growth was driven by robust demand for its computer vision chips, which are used in Internet-of-Things-enabled security cameras and automotive cameras, two areas that are growing rapidly.

Man and woman high-fiving in a car with a case of cash in between them.

Image source: Getty Images.

Contributing 60% of total revenue in fiscal 2021, the IoT-enabled camera is moving the needle in a big way for the company right now. And this market seems built for long-term growth, clocking a compound annual growth rate of nearly 13% for the next five years, according to IDC. The firm estimates that the video surveillance camera market could hit $49 billion in revenue by 2025.

As a result, the demand for Ambarella's chips that power such cameras should keep growing, especially considering that surveillance cameras are becoming more advanced. Ambarella estimates that the global security camera market had an installed base of 900 million units in 2020. However, around 250 million of those were first-generation analog cameras, which are witnessing a decline in demand. Ambarella doesn't provide chips for these first-generation cameras, which places it in a solid position to take advantage of the upgrade cycle underway.

The second-generation networked cameras that account for the majority of the security camera market are expanding Ambarella's addressable market thanks to higher content. What's more, third-generation artificial intelligence-enabled security cameras are now gaining traction -- and that's good news for Ambarella, as they carry twice the chip content compared to second-generation cameras.

Ambarella also points out that security cameras are upgraded every four to six years. This means that the company should see an increase in content per unit as customers upgrade to second- or third-generation cameras.

However, it is the automotive business where Ambarella could make serious money in the long run. This segment accounted for 15%-20% of the chipmaker's revenue in fiscal 2021, but it is expected to present a larger revenue opportunity for the company in the future that could exceed the IoT camera market. That's not surprising, as the number of cameras in vehicles has been growing at a nice clip.

Ambarella points out that each new vehicle manufactured last year had 1.5 cameras on average. Future vehicles are likely to come out with camera counts in the double digits to support autonomous driving features. As a result, Ambarella sees an addressable opportunity worth almost $5 billion in the automotive market through 2025, which is significantly higher than the $1.4 billion opportunity the company saw from this space in 2019.

Ambarella has generated $267 million in revenue over the trailing 12 months, so the automotive market alone could be a huge growth driver in the future. Analysts expect Ambarella's earnings to grow at an annual pace of 82% over the next five years, which doesn't seem surprising given the pace at which its end-markets are growing.

Investors don't want to miss out on this outstanding growth, which is probably why they have been loading up on this tech stock at a time when the broader market has been under pressure.

A woman wearing a hat stands on a street corner looking at a smartphone as a red bus passes behind her.

Image source: Getty Images.

2. Match Group

The online dating space is expected to generate more than $10 billion in revenue by 2026 as per a third-party estimate. Match Group, which has generated just under $2.7 billion in revenue in the past year, is one of the best ways to tap into this market given its dominant position. In terms of revenue, it has six of the top 10 dating apps in the U.S., with Tinder alone accounting for 40% of the U.S. revenue share.

Match Group's dominance has resulted in impressive financial growth. The company's second-quarter revenue increased 27% year over year to $708 million, driven by a 15% increase in the number of paying subscribers to 15 million. Tinder accounted for the majority of Match's user base last quarter with 9.6 million paying subscribers. Direct revenue from Tinder increased 26% year over year during the quarter to $399 million.

More importantly, revenue from Match's other online dating properties increased 28% over the year-ago quarter. Other brands recorded a 12% increase in the number of paying subscribers, while revenue per paying subscriber was up 14% over the prior-year period. A closer look at Match's business indicates that it is witnessing robust growth from its new online dating properties, while the established brands have regained their mojo.

Match's revenue from its established brands increased 13% year over year to $192 million in Q2. For comparison, the segment's revenue was down 2% year over year in the prior-year period. Meanwhile, direct revenue growth from new brands accelerated to 71% year over year last quarter compared to 65% in the year-ago quarter. Additionally, Match management points out that the "propensity to pay has improved significantly" at Tinder.

These tailwinds are the reason why Match is on track to sustain its robust growth. The company anticipates 23% to 26% year-over-year growth in revenue this quarter to a range of $790 million to $805 million. And the company's emerging brands are expected to more than double in the second half of 2021.

Analysts expect the company's earnings to increase at an annual pace of nearly 30% for the next five years. Not surprisingly, shares of Match Group have been soaring in the midst of a market correction despite its rich valuation.

The stock trades at 89 times trailing earnings and 43 times forward earnings, while its price-to-sales ratio of 17 is significantly higher than the 2020 average of 6.6. However, Match's fast pace of growth and the massive opportunity ahead support those rich multiples, which is why investors on the hunt for a growth stock have been buying its shares hand-over-fist.