AEIS vs NOVT vs MKSI vs ONTO

For growth investors, Advanced Energy Industries, Inc.

(AEIS) is the stronger pick with 21. 4% revenue growth year-over-year, versus 1. 8% for Onto Innovation Inc. (ONTO). MKS Inc. (MKSI) offers the better valuation at 68. 8x trailing P/E (30. 4x forward), making it the more compelling value choice. Analysts rate Advanced Energy Industries, Inc. (AEIS) a "Buy" — based on 24 analyst ratings — the highest consensus in this comparison. The "better buy" depends entirely on your goals: growth investors should weight revenue trajectory, value investors should weight P/E and PEG, and income investors should weight dividend yield and streak.

On trailing P/E, MKS Inc.

(MKSI) is the cheapest at 68. 8x versus Onto Innovation Inc. at 98. 6x. On forward P/E, MKS Inc. is actually cheaper at 30. 4x. The PEG ratio (P/E divided by earnings growth rate) is the most growth-adjusted single valuation metric: Onto Innovation Inc. wins at 1. 12x versus Advanced Energy Industries, Inc. 's 21. 57x — a reasonable growth-adjusted valuation.

Over the past 5 years, Onto Innovation Inc.

(ONTO) delivered a total return of +312. 6%, compared to +5. 7% for Novanta Inc. (NOVT). Over 10 years, the gap is even starker: ONTO returned +1432% versus MKSI's +750. 6%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.

By beta (market sensitivity over 5 years), Novanta Inc.

(NOVT) is the lower-risk stock at 2. 02β versus Onto Innovation Inc. 's 2. 66β — meaning ONTO is approximately 31% more volatile than NOVT relative to the S&P 500. On balance sheet safety, Onto Innovation Inc. (ONTO) carries a lower debt/equity ratio of 1% versus 173% for MKS Inc. — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), Advanced Energy Industries, Inc.

(AEIS) is pulling ahead at 21. 4% versus 1. 8% for Onto Innovation Inc. (ONTO). On earnings-per-share growth, the picture is similar: Advanced Energy Industries, Inc. grew EPS 168. 5% year-over-year, compared to -31. 5% for Onto Innovation Inc.. Over a 3-year CAGR, NOVT leads at 4. 4% annualised revenue growth. Higher growth typically commands a higher valuation multiple — check whether the premium P/E or P/S is justified by the growth rate using the PEG ratio.

Onto Innovation Inc.

(ONTO) is the more profitable company, earning 13. 6% net margin versus 5. 5% for Novanta Inc. — meaning it keeps 13. 6% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: MKSI leads at 14. 4% versus 10. 9% for AEIS. At the gross margin level — before operating expenses — ONTO leads at 49. 7%, reflecting greater pricing power or product mix advantage. Stronger margins indicate durable pricing power, lower cost of revenue, or higher mix of software/services. They are one of the clearest signs of business quality.

The PEG ratio (forward P/E divided by expected earnings growth rate) is the most precise measure of undervaluation relative to growth potential.

By this metric, Onto Innovation Inc. (ONTO) is the more undervalued stock at a PEG of 1. 12x versus Advanced Energy Industries, Inc. 's 21. 57x. A PEG below 1. 5 suggests fair-to-attractive pricing relative to expected growth. On forward earnings alone, MKS Inc. (MKSI) trades at 30. 4x forward P/E versus 40. 4x for Advanced Energy Industries, Inc. — 10. 0x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for ONTO: 12. 5% to $308. 33.

In this comparison, MKSI (0.

3% yield), AEIS (0. 1% yield) pay a dividend. NOVT, ONTO do not pay a meaningful dividend and should not be held primarily for income.

For long-horizon retirement investors, Onto Innovation Inc.

(ONTO) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (+1432% 10Y return). MKS Inc. (MKSI) carries a higher beta of 2. 64 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (ONTO: +1432%, MKSI: +750. 6%), confirming both are viable long-term holds — but the lower-volatility option typically results in less emotional selling during corrections. Retirement portfolios generally favour predictability over maximum returns. Consult a financial advisor before making allocation decisions.

These companies operate in different sectors (AEIS (Industrials) and NOVT (Technology) and MKSI (Technology) and ONTO (Technology)), which means they face different economic cycles, regulatory environments, and macro sensitivities — making direct comparison nuanced.

In terms of investment character: AEIS is a mid-cap high-growth stock; NOVT is a small-cap quality compounder stock; MKSI is a mid-cap quality compounder stock; ONTO is a mid-cap quality compounder stock. These fundamental differences mean investors should not choose between them on a single metric — the "better stock" depends entirely on which of these characteristics aligns with your investment strategy.