For 18 months, the investing community has enjoyed a record-breaking rally. The widely followed S&P 500, which is used as a barometer of the stock market's health, has doubled in value since hitting its bear-market low on March 23, 2020. What's more, we've not witnessed a correction of even 5% in 10 months. It's been the true "running of the bulls."

But despite this historic move, a number of top stocks haven't been participating in this young bull market. The following high-growth, innovative businesses have been at least halved from their 52-week highs, yet they all show significant long-term promise.

Scissors cutting a one hundred dollar bill in half.

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PubMatic: Down 64% from its 52-week high

First up is fast-paced programmatic ad-tech company PubMatic (PUBM 1.28%), which has nearly lost two-thirds of its value since hitting its 52-week high. Though I've pounded the table a lot on PubMatic of late, I do so because programmatic digital ads are no-brainer double-digit growth opportunity for the foreseeable future.

PubMatic operates a cloud-based, sell-side, programmatic ad platform. Or, in English, it works with publishers to help them sell their display space to advertisers. As time passes, we're seeing more ads go digital, with the machine-learning algorithms employed by PubMatic helping to optimize the sale and placement of ads.

Even though PubMatic's goal is to take the tedious work of buying, selling, and optimizing ads off the plate of its publishing clients, it's interesting to note that it's not always placing the highest-priced ad into an available display space. Rather, it's placing what's believed to be the most relevant ad in front of users. This tends to keep advertisers happy, and it ultimately puts pricing power in the court of its publishing clients.

In PubMatic's most recent investor presentation, the company laid out the expectation that global digital ad spend would grow by a 10% annual average through mid-decade.  This includes a forecast of double-digit mobile, video, and connected TV (CTV)/over-the-top (OTT) programmatic ad growth. Meanwhile, PubMatic's sales growth has more than doubled up the global digital ad growth rate, with CTV/OTT sales up 108% from the prior-year period in the latest quarter. To boot, the company processed over 20 trillion impressions in Q2, which was effectively double the number of impressions from the year-ago quarter. 

I could rattle favorable numbers off all day. The key point is this: advertising is going digital and PubMatic's cloud-based infrastructure is positioned perfectly to take advantage of the fastest growing aspects of this shift. Since it's already profitable on a recurring basis, the more-than-halving of its share price simply doesn't make sense.

Multiple clear jars packed to the brim with dried cannabis buds, with one tipped over.

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Trulieve Cannabis: Down 51% from its 52-week high

It's no secret that investors have a habit of overestimating the growth trajectory or uptake of next-big-thing industries. There have been a couple of bubble-esque moments in the cannabis space over the past decade. But with the U.S. pot industry maturing and a couple of companies hitting recurring profitability, it makes absolutely no sense why Trulieve Cannabis (TCNNF -3.66%) has lost a shade over half its value since hitting a 52-week high.

To begin with, the U.S. weed industry is the envy of the world. If estimates from New Frontier Data prove accurate, legal pot sales could top $41 billion by 2025. We've already had 36 states legalize medical marijuana, and half of these states have laws on their books allowing for the consumption and/or retail sale of adult-use weed now or in the future. In other words, marijuana stocks don't need federal legalization to grow and be prosperous.

Here's the real kicker: Trulieve has been profitable on a recurring basis for a longer period of time (more than three years) than any other multistate operator or direct cannabis player. This profitability is a reflection of its unique growth strategy.

To use a baseball analogy, most U.S. multistate operators (MSOs) are trying to hit as many home runs as possible. By this I mean they're planting their proverbial flag in as many legalized states as reasonable. As for Trulieve, it's opened 102 dispensaries nationwide, but has 91 of these retail locations in a single state: Florida.  By concentrating its efforts on medical marijuana-legal Florida, Trulieve has been able to effectively build up brand awareness, keep its marketing costs down, and quickly push into the profit column. In fact, Trulieve controls approximately half of the Sunshine State's dried cannabis flower and oils market share.

What'll take Trulieve to the next level is its acquisition of MSO Harvest Health & Recreation (HRVSF). What makes this deal so intriguing is Harvest Health's leading market share (15 dispensaries) in its home state of Arizona. The Grand Canyon State legalized recreational weed in November and commenced sales two months later. This deal might allow Trulieve to dominate Arizona's market, as well.

A person using a tablet to conduct a virtual visit with a doctor.

Image source: Getty Images.

Teladoc Health: Down 54% from its 52-week high

A third top stock that's been chopped in half and is been a complete head-scratcher for investors is Teladoc Health (TDOC 2.00%). As its name implies, Teladoc provides telemedicine services that connect patients with physicians.

Teladoc was a clear-cut winner in 2020. With the pandemic sweeping around the globe, physicians sought to keep patients out of offices and hospitals as much as reasonably possible. This meant turning to virtual visits. Last year, Teladoc's virtual visits more than doubled from to 10.59 million from 4.14 million in 2019.

The concern has been that Teladoc's growth rate would slow significantly once the U.S. vaccination campaign ramped up. However, this concern overlooks the plain-as-day shifts we're witnessing in the healthcare landscape with regard to personalized care.

Teladoc's platform won't replace all in-person care, but it can both improve patient care and lower overall care costs. It's far more convenient for patients, and it's a particularly powerful tool for physicians who might need to keep close tabs on patients with chronic illnesses. Since virtual visits are already billed at a lower rate than office visits, the added likelihood of improved patient outcomes means even less money out of the pockets of insurers.

Teladoc has another weapon in its arsenal, too. Teladoc acquired leading applied health signals company Livongo Health in the fourth quarter of 2020. Livongo caters to chronic-care patients by sending tips and nudges to help them lead healthier lives. It had 715,000 enrolled members as of the end of June, and plans to vastly expand its services beyond just diabetic patients to also include those with hypertension and weight control management issues. This means a large percentage of the U.S. adult population may qualify for its services.

As a truly transformative personalized care company, it makes little sense why Teladoc has fallen so far.