The Nasdaq-100 Technology Sector index has been seeing some positive turnaround since the middle of March, gaining 20% as investors seem to have regained their confidence in tech stocks after a terrible start to the year.

The broader market rally has given shares of Meta Platforms (META 3.51%), Marvell Technology Group (MRVL -0.98%), and Nvidia (NVDA 1.18%) a big shot in the arm.

But investors who haven't bought these tech stocks yet still have an opportunity to go long, as they can be bought at relatively attractive valuations. Let's look at the reasons why Meta, Marvell, and Nvidia are worth buying right now.

MRVL Chart

MRVL data by YCharts.

1. Meta Platforms

Meta Platforms stock is trading at just 16 times trailing earnings and 5.4 times sales despite rallying impressively over the past few days. These multiples make buying the stock a no-brainer right now as it is trading at a big discount to the Nasdaq-100's price-to-earnings (P/E) ratio of 33. The sales multiple is also lower than Meta's five-year average multiple of 10.3.

Throw in the fact that Meta's earnings are expected to grow at an annual rate of close to 20% for the next five years, and it becomes easy to see that investors are getting a good deal on the stock. However, it won't be surprising to see Meta's earnings grow at a faster pace as the company is on track to benefit from the fast-growing digital advertising market as well as the metaverse.

Global digital ad spending stood at $492 billion last year, according to third-party estimates, which puts Meta's market share at 23% since it generated $115 billion in ad revenue last year. It is worth noting that Meta's ad revenue shot up 37% in 2021, outpacing the 29% growth in digital ad spending last year, leading to a slight increase in the company's market share.

Man in glasses holding a smartphone.

Image source: Getty Images.

According to third-party estimates, global digital ad spending could exceed $645 billion by 2024, which should pave the way for incremental growth at Meta given its robust market share. What's more, digital ad spending is expected to cross $1 trillion by 2027, indicating that Meta is sitting on a secular growth opportunity.

The metaverse, meanwhile, could add to the multibillion-dollar advertising market by opening another avenue for digital marketers to tap into. The metaverse is a virtual, 3D world where avatars of real people could interact with each other. Though the concept is in its nascent phase, it is expected to take off substantially. According to a third-party estimate, the metaverse could grow at an annual rate of 39% through 2030.

Not surprisingly, companies have already started making their presence felt in the metaverse, setting up virtual stores and studios. Meta Platforms was the leader in the market for augmented reality/virtual reality (AR/VR) headsets last year with a share of 78%. Headsets are the key to entering the metaverse, so Meta can use its solid market share in the headset market to make a dent in the virtual advertising space. Its Oculus Quest 2 is the most popular AR/VR device on sale now.

All of this indicates that Meta Platforms has a bright future ahead that should help the stock sustain its terrific growth momentum.

2. Marvell Technology Group

Chipmaker Marvell Technology is a fast-growing tech stock that can be scooped up at an enticing valuation right now. The stock is trading at 22 times trailing earnings, a discount to the Nasdaq-100's multiple of 33. Buying the stock at this valuation looks like the right thing to do given its terrific growth.

Marvell's revenue for fiscal 2022 was up 50% over the prior year to $4.46 billion, while adjusted earnings per share increased 71% to $1.57 per share. Analysts expect Marvell to sustain its momentum in the new fiscal year as well, estimating 37% revenue growth and a 46% increase in earnings per share.

It isn't surprising to see why Marvell is expected to grow at such an impressive pace once again this year. The company's chips are used in multiple fast-growing applications that include data centers, automotive, networking, and 5G networks, and the good part is that Marvell's offerings are witnessing solid demand.

For instance, in the data center market, Marvell said on the March earnings conference call that it scored more than a dozen design wins across multiple cloud customers last fiscal year. The company anticipates the new design wins to start contributing to its revenue from fiscal 2024. More specifically, Marvell estimates $400 million in additional revenue in fiscal 2024 from its new design wins with cloud customers, which could increase to $800 million in incremental revenue in 2025.

The data center business produced $1.78 billion in revenue for Marvell last year -- accounting for 40% of the top line -- and management's comments indicate that it is set to take off impressively in the next couple of fiscal years.

On the other hand, the growing adoption of 5G technology is accelerating the growth of Marvell's carrier infrastructure business. This segment supplied 18% of the company's revenue last quarter, recording 45% year-over-year growth. Marvell says that the rollout of 5G networks by multiple customers is driving this segment's growth. The good part is that Marvell has scored new design wins to supply chips for use in 5G base stations and has struck a partnership with Dell Technologies to help deploy open radio access networks that are expected to play a key role in the 5G rollout.

These developments indicate why Marvell expects its carrier infrastructure business to grow 40% year over year in the current quarter. More importantly, with the 5G infrastructure market set to grow at an annual pace of 53% through 2026, Marvell's carrier business should sustain its outstanding growth.

As it turns out, analysts expect Marvell to clock annual earnings growth of 42% for the next five years, which isn't surprising thanks to multiple catalysts. That's why investors looking to buy a growth stock should consider buying Marvell right away given its valuation.

3. Nvidia

At 74 times trailing earnings, Nvidia is not a cheap stock to buy. However, growth-oriented investors with an appetite for risk may find Nvidia an attractive bet right now despite its rich multiple for two reasons.

First, the stock is trading at a discount as compared to last year's earnings multiple of 90. Second, Nvidia recently revealed that it has a massive addressable market worth $1 trillion spread across several fast-growing industries that include gaming, automotive, artificial intelligence software, Omniverse software, and semiconductors.

For comparison, Nvidia had generated $26.9 billion in revenue last fiscal year, up 61% from the prior year. The huge size of Nvidia's addressable market indicates that its hot growth could continue for years to come. Not surprisingly, analysts expect Nvidia's earnings to grow at 30% a year for the next five years, though the company could exceed that given the potential revenue opportunity that lies ahead of it.

For instance, Nvidia sees a $100 billion revenue opportunity in gaming. This segment generated $12.4 billion in revenue for the company last year, and the good part is that Nvidia is well placed to grow this business at a terrific pace thanks to its solid market share in this space. Jon Peddie Research estimates that Nvidia had 81% of the discrete graphics card market under its control at the end of 2021. The company is unlikely to lose its solid grip over this market thanks to a massive upgrade cycle.

Nvidia estimates that only 29% of its installed base is using its latest RTX cards, with the remaining using graphics cards that are at least two generations old. What's more, the users upgrading to Nvidia's RTX cards are spending $300 more on each card as compared to prior generations. As a result, Nvidia should continue enjoying an increase in both graphics cards volumes and average selling prices.

Meanwhile, Nvidia sees a $300 billion revenue opportunity in the automotive market. It has already secured an $11 billion design win pipeline to tap the same for the next six years thanks to partnerships with several OEMs (original equipment manufacturers) and component suppliers.

As such, investors who haven't bought Nvidia following its slide in recent months still have an opportunity to do so, and they should consider acting quickly before the stock becomes more expensive.