Cathie Wood, the CEO of investment management firm Ark Invest, is well-known on Wall Street for investing in disruptive companies. This strategy has reaped rich rewards this year as her firm's flagship ARK Innovation ETF has jumped an impressive 43% so far in 2023.

Here's a closer look at two companies from Cathie Wood's flagship fund that have delivered impressive gains this year. More importantly, Ark Invest continues to put more money into these two names -- Palantir Technologies (PLTR 3.73%) and The Trade Desk (TTD 1.67%). This isn't surprising as they're playing a disruptive role in fast-growing markets.

Let's look at the reasons Wood is buying more shares of these companies and see if they could turn out to be solid long-term investments.

1. Palantir Technologies

Palantir Technologies stock has shot up a whopping 232% in 2023, and Cathie Wood's Ark Innovation ETF has continued to increase its stake in the company in recent months. Ark Innovation bought almost 2 million shares of Palantir in August and September despite the tremendous appreciation in the stock price.

This suggests Wood has confidence in Palantir's ability to deliver more upside, which is not surprising. The company is sitting on a lucrative opportunity, especially in artificial intelligence (AI).

Wedbush Securities analyst Dan Ives estimates that Palantir could win big from AI thanks to the increasing use cases of this technology and its large ecosystem of customers and partners. Ives points out that Palantir could be sitting on a $1 trillion revenue opportunity thanks to AI. That's significantly higher than the $119 billion total addressable market (TAM) the company estimates from its core business of building and deploying software platforms to both government agencies and commercial customers.

The good part is that Palantir is already on its way to making the most of this opportunity. According to market research firm IDC, Palantir was the top provider of AI software platforms in 2021 in terms of both market share and revenue. This explains why the company has started winning notable AI contracts in recent months, with commercial customers in the U.S. increasingly adopting its platform to take advantage of Palantir's AI chops.

Ives estimates that Palantir could achieve $5 billion in annual revenue in 2027, which would be double its projected revenue of $2.22 billion in 2023. That translates into a compound annual growth rate (CAGR) of 22%. Given that Palantir's top line is on track to jump 16% this year, the company could achieve the faster pace of growth that Ives is estimating due to the emerging AI opportunity.

Assuming the company does hit $5 billion in revenue in 2027 and maintains its forward sales multiple of 16.6 at that time, which is a discount to its current price-to-sales ratio of 21, its market capitalization could increase to $83 billion. That points toward an 80% jump from current levels, suggesting that investors may want to follow Cathie Wood's lead and buy more of this stock for long-term gains.

2. The Trade Desk

The Trade Desk is another disruptive company that Cathie Wood's Ark Innovation ETF has scooped up recently, following the company's third-quarter earnings report, which was released on Nov. 9. Shares of the advertising technology (adtech) provider fell sharply following its report as its guidance fell behind expectations.

Ark Invest took advantage of this decline and added 542,000 shares of The Trade Desk to the Ark Innovation ETF on Nov. 10. This wasn't surprising, as The Trade Desk operates in the fast-growing programmatic advertising market.

The Trade Desk has been growing at a healthy pace. Revenue was up 25% year over year in Q3 to $493 million. The company's full-year revenue outlook of $580 million, however, was lower than analysts' expectations of $610 million due to headwinds that could lead advertisers to reduce spending.

Even then, The Trade Desk is on track to end the year with a 22% increase in revenue to $1.92 billion. For comparison, the global digital ad market in which the company operates is estimated to grow by nearly 10%.

The reason The Trade Desk has been able to outperform the digital ad industry is because of the growing demand for programmatic advertising. This is a data-driven technology that allows advertisers and marketers to buy ads based on algorithms to help them improve audience targeting and drive greater returns on their ad spending.

Not surprisingly, advertisers are expected to increase their programmatic ad spending budgets by a whopping $300 billion through 2027. As a result, The Trade Desk should be able to sustain its healthy growth momentum and deliver more upside. The stock is up 50% in 2023, but its latest pullback means that investors can buy it at a relatively cheap 18 times sales, as compared to its five-year average of 27.

Analysts are anticipating the company's earnings to increase at a CAGR of 24% for the next five years. However, The Trade Desk could do better than that by winning a bigger share of the digital ad market by adopting new technologies such as AI, which could open a new growth opportunity for the company. As such, investors looking to buy a stock from Cathie Wood's portfolio can consider taking advantage of The Trade Desk's latest slip since it could turn out to be a winner in the long run.