Regardless of whether you're relatively new to the stock market or have been putting your money to work on Wall Street for decades, this has been a challenging year.

Since touching new closing highs during the first week of January, the nearly 126-year-old Dow Jones Industrial Average and widely followed S&P 500 have entered correction territory, with respective declines of 12.5% and 16.1%. The sell-off has been even more pronounced in the growth-focused Nasdaq Composite, where the peak-to-trough move since hitting its all-time high in November was nearly 30% last week.

A visibly concerned person looking at a rapidly rising then plunging stock chart on a tablet.

Image source: Getty Images.

While there are a number of reasons behind this sell-off, tech stocks are shouldering a lot of the blame. The industry that led throughout most of 2021 has turned into a cement block tied around Wall Street's proverbial ankles.

But where there's fear, there's often opportunity for patient investors. During the 2022 tech wreck, the following three stocks have fallen as much as 90% from their all-time highs. Although near-term headwinds remain, they're now at levels where they can comfortably be considered screaming buys.

CrowdStrike Holdings: 48% below its all-time high

The first screaming buy amid the tech stock carnage is cybersecurity company CrowdStrike Holdings (CRWD -2.95%), which has been nearly halved since hitting its all-time intraday high roughly six months ago.

The prevailing concern with most tech stocks is that historically high inflation, and the Fed stomping on the brakes by raising interest rates and ending quantitative easing measures, will send the U.S. into a recession. Since tech stocks are traditionally cyclical, a recession would likely lead to downward earnings revisions across the board.

However, CrowdStrike has a trick up its sleeve. Over the past two decades, cybersecurity has evolved into a basic necessity. No matter how well or poorly the U.S. economy and stock market are performing, robots and hackers don't take time off from trying to steal enterprise and consumer data. As more businesses have pushed online and into the cloud in the wake of the pandemic, the onus of providing end-user protection has increasingly fallen on third-party providers like CrowdStrike.

Attracting new users has never been an issue. Over the past five years, CrowdStrike's compound annual growth rate for subscribers has been a healthy 105%. What's far more impressive is the willingness of existing clients to spend progressively more over time. For example, the company's dollar-based net retention rate (DBNR) has consistently been above 120% for 16 consecutive quarters (four years). In simpler terms, DBNR measures how much more clients spend in the most recent quarter relative to the prior-year period. A DBNR north of 120% implies an organic growth rate among existing clients of at least 20%.

The cherry on top is that CrowdStrike's subscribers tend to stick around, as evidenced by a gross retention rate that's been hovering around 98% for the past three years. Because the company's security platform, known as Falcon, is cloud-native and relies on artificial intelligence, it's proved quite capable of quickly recognizing and responding to threats.

Two businesspeople using a laptop and whiteboard to discuss strategy during a meeting.

Image source: Getty Images.

PubMatic: 67% below its all-time high

A second beaten-down tech stock that's now a screaming buy is adtech company PubMatic (PUBM 0.62%). Shares of the company have tumbled 67% since hitting their all-time high in March 2021.

To echo what I said above, the big worry is that a U.S. recession is on the horizon, or perhaps already here. Ad spending is highly cyclical, meaning a slowdown in economic growth will almost certainly translate into companies spending less on marketing.

But there's another side to this story investors should be aware of. Even though recessions are an inevitable part of the economic cycle, they don't last very long. Comparatively, periods of economic expansion typically last years. Recessions are often the ideal time to buy ad-based companies.

More importantly, PubMatic finds itself at the center of the fastest-growing aspect of advertising: digital impressions. It's what's known as a sell-side provider, which is a fancy way of saying that it helps publishers sell their display space. While the digital ad industry is expected to grow by a little over 10% annually through the midpoint of the decade, PubMatic has delivered seven consecutive quarters with sales growth of at least 20%.

What makes PubMatic so intriguing is that it built its own cloud-based infrastructure. Not having to rely on third parties is allowing the company to recognize efficiencies as its ad business scales. In other words, it's able to keep its expenses lower than those relying on third parties, and it's seeing its margins expand quickly as a result.

With advertisers steadily shifting their ad dollars to digital platforms, PubMatic is in prime position to benefit.

An engineer plugging cables into the back of a data center server tower.

Image source: Getty Images.

Fastly: 90% below its all-time high

But the disaster du jour, at least among this list of tech wrecks, is edge-computing company Fastly (FSLY -1.20%). Since hitting their all-time high in January 2021, shares have fallen a staggering 90%.

Aside from recession fears, Wall Street has been displeased with Fastly's bottom line. During the initial stages of the pandemic, people were spending more time online, which boded well for Fastly's content-delivery network services. But as vaccination rates have ticked up and life has somewhat returned to normal (or at least, folks aren't spending as much time online anymore), Fastly's quarterly losses have stood out like a sore thumb.

Although it's true that Fastly's near-term sales growth and net-loss outlook are disappointing, that ignores the bigger picture: Getting content securely and quickly to end users is becoming more important over time. If the company wants to thrive many years from now, Fastly has to put in the work now to grow its infrastructure. For some context, the company's global network capacity (in terabytes per second) has nearly doubled in the past two years.

The reason I chose to add to my position in Fastly last week has to do with the company's dollar-based net expansion rate. Despite slowing, it was still a respectable 118% in the first quarter of 2022. Not only has Fastly retained more than 99% of revenue from its clients in each of the past two years, but existing customers spent 18% more in the first quarter than they did during the comparable quarter a year ago.

Fastly is also an intriguing play on the metaverse -- a 3D virtual world that allows connected users to interact with each other and their environment. Although it will take years to develop the infrastructure needed to support widely used metaverses, Fastly is expected to help reduce latency (the lag when a connected user initiates an action).

For long-term investors, Fastly has the look of a screaming bargain.