We're now three months deep into 2023, and some stocks squeezed a lot of juice out of their first-quarter performance. The market is higher this year, but a handful of stocks have already more than doubled. Some of the names might surprise you.

Some of the names you might know are Carvana (CVNA 0.68%), Duolingo (DUOL -1.86%), and Fastly (FSLY). Let's take a closer look at these three unlikely leaders that hit the ground running in 2023.

1. Carvana: Up 107%

You might live in a city where a Carvana multilevel glass-enclosed vending machine is a skyline icon. If not, you've probably seen one of its ads. Carvana sells used cars nationwide, and its aggressive expansion at one point served up 23 consecutive quarters of triple-digit growth.

Two people enjoying a drive in a car.

Image source: Getty Images.

Last year was rough for Carvana for a couple of reasons. We can start with the end of the boom for secondhand vehicles. Demand and prices for used cars took off early in the pandemic when there was a shortage of new cars available, but that trend reversed when supply chain constraints eased in 2022 and that new-car smell became a showroom staple again.

The other problem is that the car reseller took on a lot of debt during its breakneck expansion, and with borrowing costs skyrocketing as interest rates revved up last year, Carvana creditors started to get nervous

The risks of going under are still real at Carvana. It's shaving costs, but bondholders reportedly aren't keen on its restructuring efforts. Wedbush analyst Seth Basham put out a bearish note two weeks ago, arguing that a recent exchange offer for unsecured bonds may not be enough. 

With business expected to decline this year, Carvana's negotiating leverage may continue to deteriorate with its creditors. Basham is sticking to his $1 price target, even as the shares approach double digits.

2. Duolingo: Up 101%

The most valuable company by market cap to more than double in the first quarter is another household name. Duolingo's language-learning app has been popular for a few years now, but its recent surge is truly impressive. 

The biggest catalyst to the stock's pop came at the end of February, when it posted blowout financial results. Revenue rose a better-than-expected 42% to $103.8 million in the fourth quarter. Its monthly active users have climbed to 60.7 million over the past year, a healthy 43% jump. Daily engagement is even stronger, as daily active users have spiked 62% to 16.3 million as 2022 played out.

Duolingo's CEO claims that his language software experienced growth in every region of the world, and that makes sense. International travel restrictions finally started to ease up late last year. There's a lot of pent-up travel demand, and that's a great reason to brush up on a foreign language. 

Profitability has been a problem for Duolingo, but its fourth-quarter report was also notable on the bottom line. The $0.35-a-share loss it posted was considerably better than the $0.53-a-share deficit that Wall Street pros were modeling. In Duolingo's defense, it posted less red ink than the market was forecasting every quarter of 2022. 

The outlook is where a solid report becomes spectacular. Duolingo's guidance calls for $530 million to $542 million in revenue this year, a 45% top-line jump at the midpoint. Analysts were only holding out for $464.5 million. The news gets even better on the earnings front, as the $48.6 million to $59.8 million is more than triple the $15.5 million it delivered in 2022.  

3. Fastly: Up 117%

Another stock on the rise after a head-turning quarterly update is Fastly. The edge-computing specialist was a market darling a few years ago, growing quickly and helping a growing number of businesses accelerate the delivery of their digital content. It then lost a key account -- cough, cough, TikTok -- and stumbled out of favor with investors. 

Fastly exceeded Wall Street expectations on both ends of the income statement in February's fourth-quarter report. Like Duolingo, its guidance was also refreshing. Two days before the well-received financials, Fastly stock received a rare double upgrade from Bank of America analyst Tal Liani.

New management's effort to streamline Fastly's product portfolio, pricing, and operations could be the key to improving margins. With revenue growth accelerating in the second half of 2022, the recovery plan appears to be working on the top line, too.