The Nasdaq Composite index is down by about 10% so far this year as investors remain concerned about the outlook for many businesses, particularly as President Donald Trump's tariffs pose significant risks to the U.S. economy and analysts worry that they may push the country into a recession.

The Nasdaq-100, meanwhile, is down by more than 7%. That index features the 100 most valuable non-financial stocks on the exchange, but those large caps and megacaps are not immune from the effects of a broad market sell-off.

Two Nasdaq-100 stocks that have lost around half of their market capitalization this year are The Trade Desk (TTD -3.86%) and Marvell Technology (MRVL -3.44%). Are they worth buying right now, or could there be more pain to come for their shareholders?

The Trade Desk

The Trade Desk has been the worst-performing stock on the Nasdaq-100 index thus far in 2025, losing more than 54% of its value since the start of the year (as of Monday). The ad tech stock was tanking even before Trump announced his sweeping tariffs in April. The company's biggest sell-off occurred in February after it reported its fourth-quarter numbers.

While revenue grew by 22% to $741 million for the period, that was below the company's own guidance figure of $756 million. On its earnings call, management said that it "stumbled due to a series of small execution missteps" and noted that restructuring efforts had resulted in changes in its reporting structure.

The market responded by punishing the stock. It's one thing when a company misses analysts' expectations, but it's quite another when it misses its own guidance, especially when there isn't an obvious way to cast the underperformance as a one-off event. In addition, a U.S. recession would put further pressure on its ad business as companies tend to slash their marketing and advertising budgets quickly in response to worsening economic conditions.

However, the company did project revenue of at least $575 million for the first three months of 2025 -- an increase of 17% from the prior-year period. It is scheduled to reveal the actual results for the quarter on May 8.

While the stock has lost about half its value this year, it's still trading at nearly 70 times trailing earnings, yet the company's growth rate is slowing. In that context, I don't think the worst is over for the stock -- it could still go a whole lot lower.

Marvell Technology

The second-worst performer on the Nasdaq-100 so far in 2025 is Marvell Technology -- its shares have plummeted by 48%. The chipmaker has been under pressure ever since it reported uninspiring fiscal 2025 fourth-quarter numbers. But in Marvell's case, the big disappointment was with its guidance.

Management projected that for its soon-to-end fiscal first quarter, its sales would come in around $1.88 billion, whereas some analysts had been projecting as much as $2 billion. Though Marvell's guidance was actually forecasting 62% top-line growth from the prior-year period's $1.16 billion, it wasn't a rosy enough forecast for a tech company that earlier in the year was carrying a market cap in excess of $100 billion.

Plus, tariffs threaten to increase the company's costs, and if the trade war leads to a recession, Marvell's customers may cut back on chip spending, which could make things even worse for it, at least in the short run. That's a significant concern given that the business is struggling with profitability: It has reported an operating profit in just one of its past four quarters.

Currently, Marvell trades at less than 9 times its trailing revenue. That's down from a multiple of around 20 earlier this year. Yet with so much uncertainty in the markets and Marvell's margins not looking great, even at that reduced valuation, you may want to take a wait-and-see approach with the stock for now.