SOTK vs ACMR vs UCTT vs ONTO

For growth investors, ACM Research, Inc.

(ACMR) is the stronger pick with 15. 2% revenue growth year-over-year, versus -2. 1% for Ultra Clean Holdings, Inc. (UCTT). ACM Research, Inc. (ACMR) offers the better valuation at 43. 2x trailing P/E (30. 8x forward), making it the more compelling value choice. Analysts rate ACM Research, Inc. (ACMR) a "Buy" — based on 10 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, ACM Research, Inc.

(ACMR) is the cheapest at 43. 2x versus Onto Innovation Inc. at 98. 6x. On forward P/E, ACM Research, Inc. is actually cheaper at 30. 8x. The PEG ratio (P/E divided by earnings growth rate) is the most growth-adjusted single valuation metric: ACM Research, Inc. wins at 0. 87x versus Onto Innovation Inc. 's 1. 12x — a PEG below 1. 0 traditionally signals the market is underpricing earnings growth.

Over the past 5 years, Onto Innovation Inc.

(ONTO) delivered a total return of +312. 6%, compared to +18. 8% for Sono-Tek Corporation (SOTK). Over 10 years, the gap is even starker: ACMR returned +31. 0% versus SOTK's +382. 0%. 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), Sono-Tek Corporation (SOTK) is the lower-risk stock at 0.

48β versus Ultra Clean Holdings, Inc. 's 3. 21β — meaning UCTT is approximately 564% more volatile than SOTK relative to the S&P 500. On balance sheet safety, Onto Innovation Inc. (ONTO) carries a lower debt/equity ratio of 1% versus 103% for Ultra Clean Holdings, Inc. — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), ACM Research, Inc.

(ACMR) is pulling ahead at 15. 2% versus -2. 1% for Ultra Clean Holdings, Inc. (UCTT). On earnings-per-share growth, the picture is similar: ACM Research, Inc. grew EPS -10. 5% year-over-year, compared to -869. 2% for Ultra Clean Holdings, Inc.. Over a 3-year CAGR, ACMR leads at 32. 3% 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 -8. 8% for Ultra Clean Holdings, Inc. — meaning it keeps 13. 6% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: ONTO leads at 13. 2% versus 2. 1% for UCTT. 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, ACM Research, Inc. (ACMR) is the more undervalued stock at a PEG of 0. 87x versus Onto Innovation Inc. 's 1. 12x. A PEG below 1. 0 is traditionally considered the threshold for growth-adjusted undervaluation. On forward earnings alone, ACM Research, Inc. (ACMR) trades at 30. 8x forward P/E versus 38. 7x for Onto Innovation Inc. — 7. 9x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for ACMR: 26. 7% to $75. 00.

In this comparison, ACMR (0.

2% yield) pays a dividend. SOTK, UCTT, ONTO do not pay a meaningful dividend and should not be held primarily for income.

For long-horizon retirement investors, Sono-Tek Corporation (SOTK) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0.

48), +382. 0% 10Y return). ACM Research, Inc. (ACMR) carries a higher beta of 3. 17 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (SOTK: +382. 0%, ACMR: +31. 0%), 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.

Both stocks operate in the Technology sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both.

In terms of investment character: SOTK is a small-cap quality compounder stock; ACMR is a small-cap high-growth stock; UCTT is a small-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.