Is The Trade Desk Stock a Buy for 2026? Here are 3 Reasons For, and 3 Reasons Against It.

The Trade Desk (NASDAQ: TTD) enters 2026 as one of the most debated stocks in digital advertising.

The company remains a high-quality operator with strong long-term positioning. Yet the competitive landscape, once favorable, now looks more crowded than ever. As a result, investors face an increasingly nuanced question: Is The Trade Desk still a buy going into 2026?

The honest answer is that both sides of the argument deserve attention. Here are three reasons to consider buying the stock -- and three reasons to stay cautious.

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Three reasons to buy

1. The business remains fundamentally strong

Despite a more turbulent year, The Trade Desk continues to deliver solid top-line growth and high customer retention. In 2025, revenue grew in the high teens, customer retention again exceeded 95%, and the company maintained healthy margins. These indicators suggest advertisers continue to rely on the platform and see meaningful value from its tools.

The growth of connected TV (CTV) and retail media also sets up long-term tailwinds. Advertisers are shifting budgets toward measurable, data-driven channels, and The Trade Desk serves as a neutral gateway to premium inventory across the open internet. As more spending moves from linear TV to digital platforms, The Trade Desk stands to benefit from structural market growth.

2. Kokai is gaining traction and improving performance

Kokai -- the company's AI-powered platform -- emerged as one of the bright spots in 2025. Migration accelerated throughout the year, with a large majority of advertiser spend now routed through Kokai. More importantly, The Trade Desk shared measurable improvements: lower acquisition costs, better reach efficiency, and higher engagement.

These performance gains matter because they strengthen the company's value proposition at a time when advertisers want more efficiency. If Kokai continues to deliver repeatable ROI across campaign types, it could become a durable competitive advantage, helping The Trade Desk maintain relevance even as large platforms push their own AI tools.

3. Long-term optionality remains intact

The Trade Desk remains at the intersection of several rapidly expanding markets. CTV, retail media, digital audio, and global programmatic remain underpenetrated relative to their long-term potential. As an independent DSP, the company can participate across almost every channel, without tying itself to one ecosystem's data or content.

That optionality provides The Trade Desk with long-term growth levers. As digital advertising matures globally, the company can scale into new markets, publishers, and channels. Even modest execution can compound meaningfully over time.

Three reasons to stay cautious

1. Competition intensified dramatically

This year marked a shift in competitive dynamics. Amazon's advertising business gained traction, joining the ranks of its larger peers, Alphabet's Google and Meta Platforms. In particular, its programmatic partnership with Netflix gave Amazon direct access to some of the most valuable streaming inventory.

For The Trade Desk, losing premium supply -- or even competing against Amazon for the same inventory -- raises risk. Meanwhile, Google and Meta continue to expand their AI-driven ad capabilities, leveraging unmatched first-party data sets. The open internet remains a substantial market, but the competition for advertiser budgets has intensified.

2. The flawless execution story is gone

The Trade Desk established its reputation by running one of the most consistent operating models in tech, having beaten its own revenue expectations for over eight years. That streak ended in late 2024, and 2025 brought more volatility than many investors were used to seeing.

To be clear, the business continues to perform well. But the psychological shift matters. Investors no longer assume autopilot excellence. When a stock trades at premium multiples, even small execution hiccups can create outsized swings in sentiment. The Trade Desk must now prove reliability quarter after quarter.

And that brings us to the final reason to be cautious.

3. The stock still carries a premium valuation

Despite the pullback, The Trade Desk remains expensive. As of this writing , it trades at a price-to-earnings (P/E) ratio of 46. For comparison, Alphabet trades at a P/E ratio of 32. Those valuations require strong growth and stable margins -- not uncertainty around supply access and intensifying competition.

If the company reaccelerates growth or expands margins, investors can justify paying for that valuation. But without clear signs of operating momentum, the risk-reward remains unappealing for conservative investors.

So, is the stock a buy for 2026?

The Trade Desk remains a strong business with robust customer loyalty, a powerful AI platform, and exposure to multi-year trends in digital advertising.

Still, investors should not disregard the challenges ahead: Competitive pressure has increased, execution expectations have reset, and the valuation still demands solid execution.

For long-term investors, the best approach may be a conditional buy: Consider a small position if you believe in the company's multiyear trajectory, but wait for either a better valuation or clearer evidence of Kokai-driven performance before buying aggressively.

Lawrence Nga has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Alphabet, Amazon, Meta Platforms, Netflix, and The Trade Desk. The Motley Fool has a disclosure policy.