ONTO Stock Climbs 26% in a Month: What's the Next Move for Investors?

Shares of Onto Innovation, Inc. ONTO have surged 25.5% over the past month compared with the Zacks Nanotechnology industry’s growth of 24.7%. The company has outpaced the Zacks Computer and Technology sector and the S&P 500 composite’s plunge of 4.3% and 0.9%, respectively. The rally reflects growi…

Shares of Onto Innovation, Inc. ONTO have surged 25.5% over the past month compared with the Zacks Nanotechnology industry’s growth of 24.7%. The company has outpaced the Zacks Computer and Technology sector and the S&P 500 composite’s plunge of 4.3% and 0.9%, respectively. The rally reflects growing investor optimism surrounding the company's exposure to AI, advanced semiconductor packaging and HBM manufacturing. As chipmakers continue to invest aggressively to meet demand for AI infrastructure, Onto Innovation has emerged as one of the beneficiaries of this trend.

ONTO’s key competitors include KLA Corporation KLAC, Camtek Ltd CAMT and Nova Ltd. NVMI. KLAC has grown 25.3%, while CAMT and NVMI plummeted 15.2% and 5.2%, respectively, in the same time frame.

After such a sharp move, however, investors naturally face an important question: Is it still worth buying ONTO, or has the rally already priced in most of the good news? Let's examine what's driving the stock higher, the company's long-term prospects and whether investors should buy, hold, or wait for a better entry point.

Advanced Packaging Becomes a Major Growth Driver for ONTO

The company sees high growth potential in advanced packaging, silicon photonics, panel-level packaging and related applications. Advanced packaging is expected to grow more than 50% in 2026, driven by the rapid expansion of AI and next-generation semiconductor technologies. Silicon photonics is already moving into volume production as AI servers require faster data transfer and lower power consumption. The panel-level packaging market, currently valued at roughly $200 million, also has significant room for expansion as the industry increasingly adopts panel-based manufacturing and chiplet architectures.

At the same time, demand for smaller and denser interconnects, with bump sizes below 6 microns, continues to rise, creating additional opportunities across the advanced packaging ecosystem. Despite ongoing supply chain headwinds, lead times remain well-managed, and companies have reported no major impact on customer commitments or delivery schedules. Onto Innovation sees a strong growth runway in the 2.5D logic market, supported by deeper engagement with a key customer and an expanding set of applications. Previous system limitations have been removed, enabling the company to pursue more than 15 applications that were previously out of reach, expanding its serviceable addressable market.

Management also indicated that its current outlook may be conservative, leaving room for upside in the second half of the year, with the momentum expected to extend into 2027 as customer adoption broadens. At the same time, the company is benefiting from a more diversified customer base, as advanced packaging customers increasingly outsource high-value process steps. By strengthening its position with outsourced manufacturing partners, ONTO is reducing customer concentration, expanding its market reach and building a more diversified and sustainable long-term revenue base.

ONTO continues strengthening its competitive edge through multiple product wins and market expansion efforts. Its Dragonfly G5 inspection system has been qualified by a top 2.5D logic customer, with shipments already ahead of schedule and demand expected to grow through 2026. Further, the Atlas G6 platform is gaining momentum in advanced-node manufacturing, with management predicting 25% growth in 2026. A new through-silicon via metrology application is set for initial shipments in the second half of 2026.

For 2027, it anticipates outpacing wafer fab equipment industry growth through ongoing market share gains, driven by Dragonfly G5's nearly $1 billion addressable market, the continued expansion of Atlas G6 in gate-all-around applications, new surface charge metrology and panel-level packaging offerings and a strong pipeline of new applications for a wider customer base.

Risks Faced By ONTO

Despite its strong long-term prospects, Onto Innovation faces several risks. The semiconductor equipment industry remains highly cyclical, making customer spending vulnerable to shifts in inventory levels and end-market demand. The company also relies on a handful of large semiconductor customers, leaving results exposed to delays in capital spending. In addition, export controls and geopolitical tensions continue to create uncertainty for semiconductor equipment suppliers, potentially limiting future growth opportunities. Intense competition from larger industry players further pressures Onto Innovation to continue heavy R&D investments to maintain its technological edge.

Favorable Estimate Revision Trend for ONTO

Earnings estimates for ONTO have moved up for both 2026 and 2027 over the past 60 days.

Is ONTO’s Valuation Becoming Stretched?

Valuation is the primary concern after ONTO's 26% rally, with semiconductor equipment stocks typically trading at rich multiples during upcycles. In terms of forward price/earnings, ONTO’s shares are trading at 41X, higher than the industry’s 8.05X.

KLAC, CAMT and NVMI are trading at multiples of 71.69X, 43.13X and 47.12X, respectively.

Should Investors Buy, Hold or Fold ONTO Stock?

Onto Innovation has become one of the more compelling semiconductor equipment companies benefiting from the AI boom. The recent rally reflects investors' growing confidence in these opportunities, but it also raises valuation expectations. While the stock may experience near-term volatility after such a sharp advance, the company's long-term fundamentals remain solid.

For existing shareholders, the recent surge reinforces the strength of Onto Innovation's business model and supports a hold stance, particularly for those with a multi-year investment horizon. For prospective investors, the company remains attractive, but initiating a position gradually or waiting for a pullback could offer a more balanced entry point.

ONTO currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

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