Sifting through countless of stocks in the Semiconductors & Semiconductor Equipment industry can be tedious, and sometimes two stocks are just too similar to judge which is the better investment. If you’re on the fence about investing in Amkor Technology, Inc. or Onto Innovation Inc. because you’re not sure how they measure up, it’s important to compare them on a few factors before making your decision.

Read on to learn how Amkor Technology, Inc. and Onto Innovation Inc. compare based on key financial metrics to determine which better meets your investment needs.

About Amkor Technology, Inc. and Onto Innovation Inc.

Amkor Technology, Inc. provides outsourced semiconductor packaging and test services in the United States, Japan, Europe, and the Asia Pacific. It offers turnkey packaging and test services, including semiconductor wafer bump, wafer probe, wafer back-grind, package design, packaging, burn-in, system-level and final test, and drop shipment services; flip chip scale package products for smartphones, tablets, and other mobile consumer electronic devices; flip chip stacked chip scale packages that are used to stack memory digital baseband, and as applications processors in mobile devices; flip-chip ball grid array packages for various networking, storage, computing, automotive, and consumer applications; and memory products for system memory or platform data storage. The company provides wafer-level CSP packages for power management, transceivers, sensors, wireless charging, codecs, and specialty silicon; wafer-level fan-out packages used in power management, transceivers, radar, and specialty silicon; silicon wafer integrated fan-out technology that replaces a laminate substrate with a thinner structure; leadframe packages for electronic devices and mixed-signal applications; and substrate-based wirebond packages used to connect a die to a substrate. In addition, it offers micro-electro-mechanical systems packages that are miniaturized mechanical and electromechanical devices; and advanced system-in-package modules used in radio frequency and front end modules, basebands, connectivity, fingerprint sensors, display and touch screen drivers, sensors and MEMS, and NAND memory and solid-state drives. Further, the company provides wafer, package, and system level test services, as well as burn-in test and test development services. It serves integrated device manufacturers, fabless semiconductor companies, original equipment manufacturers, and contract foundries. Amkor Technology, Inc. was founded in 1968 and is headquartered in Tempe, Arizona.

Onto Innovation Inc. engages in the design, development, manufacture, and support of process control tools that perform macro-defect inspection and metrology in the United States, Taiwan, South Korea, Japan, China, Southeast Asia, Asia, and Europe. The company offers lithography systems and process control analytical software; and automated and integrated metrology systems, silicon wafer all-surface inspection, macro defect inspection, automated defect classification and pattern analysis, yield analysis, opaque film metrology, 4D business, advanced packaging lithography, process control software, and yield management software products. It also provides process and yield management solutions, and device packaging and test facilities through standalone systems for optical metrology, macro-defect inspection, packaging lithography, and transparent and opaque thin film measurements. In addition, the company offers process control software portfolio that includes solutions for standalone tools, groups of tools, and factory-wide suites. Further, it engages in systems and software, spare parts, and other services, as well as offers software licensing services; and provides advanced product lines, such as FAaST, CnCV, and MBIR. The company’s products are used in semiconductor and advanced packaging device manufacturers; silicon wafers; semiconductor integrated circuit fabricators; light emitting diodes; vertical-cavity surface-emitting lasers; micro-electromechanical systems; CMOS image sensors; silicon and compound semiconductor power devices; analog devices; RF filters; data storage; and various industrial and scientific applications. Onto Innovation Inc. was founded in 1940 and is headquartered in Wilmington, Massachusetts.

Latest Semiconductors & Semiconductor Equipment and Amkor Technology, Inc., Onto Innovation Inc. Stock News

As of September 9, 2026, Amkor Technology, Inc. had a $12.8 billion market capitalization, compared to the Semiconductors & Semiconductor Equipment median of $4.9 million. Amkor Technology, Inc.’s stock is up 26.2% in 2026, up 5.7% in the previous five trading days and up 106.81% in the past year.

Currently, Amkor Technology, Inc.’s price-earnings ratio is 23.0. Amkor Technology, Inc.’s trailing 12-month revenue is $7.5 billion with a 7.4% net profit margin. Year-over-year quarterly sales growth most recently was 25.6%. Analysts expect adjusted earnings to reach $2.572 per share for the current fiscal year. Amkor Technology, Inc. currently has a 0.7% dividend yield.

As of September 9, 2026, Onto Innovation Inc. had a $13.7 billion market cap, putting it in the 82nd percentile of all stocks. Onto Innovation Inc.’s stock is up 73.2% in 2026, up 7.4% in the previous five trading days and up 168.65% in the past year.

Currently, Onto Innovation Inc.’s price-earnings ratio is 104.0. Onto Innovation Inc.’s trailing 12-month revenue is $1.1 billion with a 11.8% net profit margin. Year-over-year quarterly sales growth most recently was 35.3%. Analysts expect adjusted earnings to reach $8.106 per share for the current fiscal year. Onto Innovation Inc. does not currently pay a dividend.

How We Compare Amkor Technology, Inc. and Onto Innovation Inc. Stock Grades

Stock evaluation requires access to huge amounts of data and the knowledge and time to sift through it all, make sense of financial ratios, read income statements and analyze recent stock movements. AAII created A+ Investor, a robust data suite that condenses data research in an actionable and customizable way suitable for investors of all knowledge levels, to help investors streamline and work through such data.

AAII’s proprietary stock grades come with A+ Investor. These offer intuitive A‐F grades for each of five key investing factors: value, growth, momentum, earnings estimate revisions and quality. Here, we’ll take a closer look at Amkor Technology, Inc. and Onto Innovation Inc.’s stock grades to see how they measure up against one another.

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Amkor Technology, Inc. and Onto Innovation Inc. Stock Value Grades

Company	Ticker	Value
Amkor Technology, Inc.	AMKR	C
Onto Innovation Inc.	ONTO	F

Successful stock investing involves buying low and selling high, so stock valuation is an important consideration for stock selection.

Buying stocks that are going to go up typically means buying stocks that are undervalued in the first place, although momentum investors may argue that point.

AAII’s A+ Investor Value Grade derives from a stock’s value score. The Value Score is the percentile rank of the average of the percentile ranks of the price-to-sales ratio, price-earnings ratio, enterprise-value-to-EBITDA (EV/EBITDA) ratio, shareholder yield, price-to-book-value ratio and price-to-free-cash-flow ratio. The score is variable, meaning it can consider all six ratios or, should any of the six ratios not be valid, the remaining ratios that are valid. To be assigned a Value Score, stocks must have a valid (non-null) ratio and corresponding ranking for at least two of the six valuation ratios.

Stocks with a Value Score from 81 to 100 are considered deep value, those with a score between 61 and 80 are a good value and so on.

Amkor Technology, Inc. has a Value Score of 56, which is Average. Onto Innovation Inc. has a Value Score of 5, which is Ultra Expensive.

The Value Stock Winner: No Clear Winner

Neither Amkor Technology, Inc. or Onto Innovation Inc. has a high enough value grade to be considered a “winner.” Investors who are considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolio. It’s important to look at a wide range of financial metrics in order to determine if Amkor Technology, Inc. or Onto Innovation Inc. is the better investment when it comes to value.

Amkor Technology, Inc. and Onto Innovation Inc.’s Quality Grades

Company	Ticker	Quality
Amkor Technology, Inc.	AMKR	C
Onto Innovation Inc.	ONTO	C

Like the Value Grade, AAII’s A+ Investor Quality Grade comes from the percentile rank of key metrics. Specifically, the Quality Score is the percentile rank of the average of the percentile ranks of return on assets (ROA), return on invested capital (ROIC), gross profit relative to assets, buyback yield, change in total liabilities to assets, accruals, Z double prime bankruptcy risk (Z) score and the F-Score.

The score is variable, meaning it can consider all eight measures or, should any of the eight measures not be valid, the remaining measures that are valid. To be assigned a Quality Score, stocks must have a valid (non-null) measure and corresponding ranking for at least four of the eight quality measures.

The Quality Score is used to assess the underlying “quality” of a particular stock. A higher-quality stock possesses traits associated with upside potential and reduced downside risk. Backtesting of the Quality Grade shows that stocks with higher grades, on average, outperformed stocks with lower grades over the period of 1998 through 2019.

Stocks receive better grades (higher scores) for having higher scores for the quality subcomponents and worse grades (lower scores) for lower scores for the subcomponents.

Amkor Technology, Inc. has a Quality Score of 59, which is Average. Onto Innovation Inc. has a Quality Score of 48, which is Average.

The Quality Stock Winner: No Clear Winner

Neither Amkor Technology, Inc. or Onto Innovation Inc. has a high enough Quality Grade to be considered a “winner.” Investors who are considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolios. It’s important to look at a wide range of financial metrics in order to determine if Amkor Technology, Inc. or Onto Innovation Inc. is the better investment when it comes to quality.

Amkor Technology, Inc. and Onto Innovation Inc.’s Estimate Revisions Grades

Company	Ticker	Earnings Estimate
Amkor Technology, Inc.	AMKR	B
Onto Innovation Inc.	ONTO	B

Earnings estimate revisions scores consider the magnitude of a company’s earnings surprise in its last two reported fiscal quarters. Often, positive surprises beget further positive surprises‐or at least continued sales growth (the exact opposite is generally true, too).

Estimate revisions offer an indication of what analysts are thinking about the short-term prospects of a firm. Estimate revisions are based on the statistical significance of a firm’s last two quarterly earnings surprises and the percentage change in its consensus estimate for the current fiscal year over the past month and past three months.

Amkor Technology, Inc. has a Earnings Estimate Score of 75, which is Positive. Onto Innovation Inc. has a Earnings Estimate Score of 71, which is Positive.

The Earnings Estimate Revisions Grade Winner: It’s a Tie!

Looking at the Earnings Estimate Revisions Grade breakdown above, both Amkor Technology, Inc. and Onto Innovation Inc. have a grade of B. For those focusing solely on a company’s estimate revisions, other financial metrics will need to be evaluated to determine whether Amkor Technology, Inc. or Onto Innovation Inc. is a better fit.

Other Amkor Technology, Inc. and Onto Innovation Inc. Grades

In addition to Estimate Revisions, Value and Quality, A+ Investor also provides grades for Growth and Momentum.

Momentum grades help uncover stocks experiencing anomalously high rates of return; research finds that stocks with high relative levels of momentum tend to outperform, whereas those with low levels of momentum tend to continue underperforming.

Growth investing builds on the idea that stocks of companies exhibiting strong, consistent and prolonged growth outperform those of slower-growth companies. AAII measures growth through consistency of annual sales growth, five-year sales growth rankings adjusted for extreme levels, and consistency of positive annual cash from operations.

These 2 key factors, when combined with the above, provide a holistic view into a particular stock. Further, by joining A+ Investor you can see whether Amkor Technology, Inc. and Onto Innovation Inc. pass any of our 60+ stock screens that have outperformed the market since their creation.

So, Which Is the Better Investment, Amkor Technology, Inc. or Onto Innovation Inc. Stock?

Overall, Amkor Technology, Inc. stock has a Value Score of 56, Estimate Revisions Score of 75 and Quality Score of 59.

Onto Innovation Inc. stock has a Value Score of 5, Estimate Revisions Score of 71 and Quality Score of 48.

Comparing Amkor Technology, Inc. and Onto Innovation Inc.’s grades, scores and metrics can act as a solid basis to determine whether they may be a good investment or not. You’ll also want to look at your portfolio’s asset allocation as well as your risk tolerance and financial goals to see if either of these stocks would make a good fit for you. AAII can help you figure out which investments align with your individual needs and preferences.

Investors are encouraged to do their own due diligence and research. In this way, individuals can effectively become managers of their own assets‐without having to rely on others for financial independence. You can count on AAII for timeless articles on financial planning and stock-picking, unbiased research and actionable analysis.

A+ Investor adds to our qualitative teaching with a powerful data suite to help you whittle down investment choices to find stocks, exchange-traded funds (ETFs) or mutual funds that meet your needs.

AAII Disclaimer

We make no representations or warranties that any investor will, or is likely to, achieve profits similar to those shown, because past, hypothetical or simulated performance is not necessarily indicative of future results. Before making an investment decision, you should consider your circumstances and whether the information on our content is applicable to your situation. This information was prepared in good faith, and we accept no liability for any errors or omissions. The full disclaimer can be read here.