AMSC vs POWI vs VICR vs MPWR vs SLAB

For growth investors, American Superconductor Corporation (AMSC) is the stronger pick with 53.

0% revenue growth year-over-year, versus 5. 9% for Power Integrations, Inc. (POWI). Vicor Corporation (VICR) offers the better valuation at 100. 1x trailing P/E (94. 3x forward), making it the more compelling value choice. Analysts rate American Superconductor Corporation (AMSC) a "Buy" — based on 15 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, Vicor Corporation (VICR) is the cheapest at 100.

1x versus American Superconductor Corporation at 332. 6x. On forward P/E, American Superconductor Corporation is actually cheaper at 15. 4x — notably different from the trailing picture, reflecting expected earnings growth. The PEG ratio (P/E divided by earnings growth rate) is the most growth-adjusted single valuation metric: Vicor Corporation wins at 2. 10x versus Monolithic Power Systems, Inc. 's 2. 48x.

Over the past 5 years, Monolithic Power Systems, Inc.

(MPWR) delivered a total return of +366. 2%, compared to -8. 3% for Power Integrations, Inc. (POWI). Over 10 years, the gap is even starker: VICR returned +27. 0% versus POWI's +232. 7%. 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), Silicon Laboratories Inc.

(SLAB) is the lower-risk stock at 1. 25β versus American Superconductor Corporation's 2. 90β — meaning AMSC is approximately 132% more volatile than SLAB relative to the S&P 500. On balance sheet safety, Monolithic Power Systems, Inc. (MPWR) carries a lower debt/equity ratio of 1% versus 2% for Vicor Corporation — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), American Superconductor Corporation (AMSC) is pulling ahead at 53.

0% versus 5. 9% for Power Integrations, Inc. (POWI). On earnings-per-share growth, the picture is similar: Vicor Corporation grew EPS 1764% year-over-year, compared to -65. 2% for Monolithic Power Systems, Inc.. Over a 3-year CAGR, AMSC leads at 27. 1% 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.

Vicor Corporation (VICR) is the more profitable company, earning 29.

1% net margin versus -8. 3% for Silicon Laboratories Inc. — meaning it keeps 29. 1% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: MPWR leads at 26. 1% versus -9. 0% for SLAB. At the gross margin level — before operating expenses — SLAB leads at 58. 2%, 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, Vicor Corporation (VICR) is the more undervalued stock at a PEG of 2. 10x versus Monolithic Power Systems, Inc. 's 2. 48x. Both stocks trade at elevated growth-adjusted valuations, so expected growth needs to materialise. On forward earnings alone, American Superconductor Corporation (AMSC) trades at 15. 4x forward P/E versus 94. 3x for Vicor Corporation — 78. 9x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for AMSC: 15. 6% to $61. 50.

In this comparison, POWI (1.

2% yield), MPWR (0. 4% yield) pay a dividend. AMSC, VICR, SLAB do not pay a meaningful dividend and should not be held primarily for income.

For long-horizon retirement investors, Silicon Laboratories Inc.

(SLAB) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 1. 25), +375. 0% 10Y return). Monolithic Power Systems, Inc. (MPWR) carries a higher beta of 2. 28 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (SLAB: +375. 0%, MPWR: +24. 9%), 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 (AMSC (Industrials) and POWI (Technology) and VICR (Technology) and MPWR (Technology) and SLAB (Technology)), which means they face different economic cycles, regulatory environments, and macro sensitivities — making direct comparison nuanced.

In terms of investment character: AMSC is a small-cap high-growth stock; POWI is a small-cap quality compounder stock; VICR is a mid-cap quality compounder stock; MPWR is a mid-cap high-growth stock; SLAB is a small-cap high-growth stock. POWI pays a dividend while AMSC, VICR, MPWR, SLAB do not, making them suitable for different income and tax situations. 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.