Over the past few months, I've bought more stocks than I ever have before in any three-month stretch. And I'm not only talking about the early days of the pandemic -- there are still some excellent long-term bargains to be found and I haven't been hesitant to put more money to work.

With that in mind, here's why I added even more to my positions in Empire State Realty Trust (NYSE:ESRT) and Boston Omaha (NASDAQ:BOMN) and why I finally decided to leave my value investor comfort zone and pull the trigger on The Trade Desk (NASDAQ:TTD).

Man looking at laptop screen with fist raised in air in celebration.

Image source: Getty Images.

Iconic assets and an opportunity to create long-term value

I'm a big fan of real estate stocks, and there's none that I've bought more of during the pandemic than Empire State Realty Trust. The company is a real estate investment trust that owns and operates office buildings in the New York City area, including the famous Empire State Building.

Empire State has been in my portfolio for some time, but after getting roughly cut in half in 2020, now could be an especially strong buying opportunity.

First, the bad. New York City is the epicenter of the coronavirus outbreak in the United States, so the stock is certainly down for a reason. The highly profitable Empire State Building Observatory remains closed, and 20% and 25% of tenants haven't paid April and May rent, respectively. And, the New York office space market was experiencing a slowdown before the pandemic.

However, there is a massive growth opportunity for patient long-term investors. Empire State has $1 billion in cash, lower leverage than its peers, and recently hired a Chief Investment Officer for the first time in the company's history to put the company's money to work. In a recent presentation, CEO Anthony Malkin says that he sees an 18-to-24-month window of opportunity in the NYC office market, and the company seems intent on taking advantage.

I've had my eye on this one for a while...

I had been considering adding The Trade Desk to my portfolio for some time and finally decided to pull the trigger recently.

The company runs a leading programmatic advertising platform, allowing advertisers to create and manage ad campaigns, and to optimize them across several formats, such as mobile, search, audio, or streaming outlets, just to name a few. There's a clear shift taking place in the advertising industry, and The Trade Desk is likely to be one of the main beneficiaries.

In less than a decade, The Trade Desk has grown from nothing into a platform where more than $3 billion in advertising dollars were spent last year, and growth continues to be impressive. Last year, The Trade Desk's revenue soared by nearly 40% from 2018 levels and with the global ad spending market estimated to be $725 billion in size, the company could be just getting started.

A ground-floor long-term growth play

Boston Omaha is often compared to an early stage Berkshire Hathaway (NYSE:BRK.A) (NYSE:BRK.B), and it's not difficult to see why. Its business model involves acquiring cash-flowing businesses, particularly insurance companies and billboard advertising businesses, which will then generate cash flow that can be reinvested in additional acquisitions or in equity securities. Plus, co-CEO Alex Rozek happens to be Warren Buffett's great-nephew (although to be clear, Buffett has nothing to do with the company).

Unlike Berkshire Hathaway, however, Boston Omaha is very small. By market cap, it's roughly 0.1% of the size of Berkshire. This is both good and bad. It means that Boston Omaha is an untested business and is therefore more of a speculative investment. On the other hand, the company's small size means that Boston Omaha has tons of opportunities to grow, and it doesn't need to focus on massive acquisitions to move the needle for investors.

Now, I'm not investing in Boston Omaha with the expectation that it will be the "next" Berkshire Hathaway. But this is an opportunity to get in on the ground floor of a time-tested business model that could produce fantastic long-term returns.

I bought all of these for the long term

I bought all three of these as long-term investments. The COVID-19 pandemic isn't over yet, and the stock market will almost certainly be more volatile than usual for the duration, so don't expect these stocks (or any other) to rise in a straight line. However, all three of these are excellent businesses and I'm excited to watch them grow over the next decade and beyond.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.