CLGN vs IDXX vs ZTS vs RGEN

For growth investors, Repligen Corporation (RGEN) is the stronger pick with 16.

4% revenue growth year-over-year, versus -95. 3% for CollPlant Biotechnologies Ltd. (CLGN). Zoetis Inc. (ZTS) offers the better valuation at 14. 5x trailing P/E (12. 4x forward), making it the more compelling value choice. Analysts rate IDEXX Laboratories, Inc. (IDXX) a "Buy" — based on 22 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, Zoetis Inc.

(ZTS) is the cheapest at 14. 5x versus Repligen Corporation at 147. 0x. On forward P/E, Zoetis Inc. is actually cheaper at 12. 4x. The PEG ratio (P/E divided by earnings growth rate) is the most growth-adjusted single valuation metric: Zoetis Inc. wins at 1. 04x versus IDEXX Laboratories, Inc. 's 2. 76x — a reasonable growth-adjusted valuation.

Over the past 5 years, IDEXX Laboratories, Inc.

(IDXX) delivered a total return of +5. 1%, compared to -97. 1% for CollPlant Biotechnologies Ltd. (CLGN). Over 10 years, the gap is even starker: IDXX returned +556. 2% versus CLGN's -95. 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), CollPlant Biotechnologies Ltd.

(CLGN) is the lower-risk stock at 0. 89β versus Repligen Corporation's 1. 76β — meaning RGEN is approximately 97% more volatile than CLGN relative to the S&P 500. On balance sheet safety, CollPlant Biotechnologies Ltd. (CLGN) carries a lower debt/equity ratio of 23% versus 3% for Zoetis Inc. — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), Repligen Corporation (RGEN) is pulling ahead at 16.

4% versus -95. 3% for CollPlant Biotechnologies Ltd. (CLGN). On earnings-per-share growth, the picture is similar: Repligen Corporation grew EPS 287. 0% year-over-year, compared to -133. 9% for CollPlant Biotechnologies Ltd.. Over a 3-year CAGR, IDXX leads at 8. 5% 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.

Zoetis Inc.

(ZTS) is the more profitable company, earning 28. 2% net margin versus -32. 3% for CollPlant Biotechnologies Ltd. — meaning it keeps 28. 2% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: ZTS leads at 38. 0% versus -33. 5% for CLGN. At the gross margin level — before operating expenses — ZTS leads at 70. 5%, 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, Zoetis Inc. (ZTS) is the more undervalued stock at a PEG of 1. 04x versus IDEXX Laboratories, Inc. 's 2. 76x. A PEG below 1. 5 suggests fair-to-attractive pricing relative to expected growth. On forward earnings alone, Zoetis Inc. (ZTS) trades at 12. 4x forward P/E versus 64. 3x for Repligen Corporation — 51. 8x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for ZTS: 63. 8% to $143. 00.

In this comparison, ZTS (2.

3% yield) pays a dividend. CLGN, IDXX, RGEN do not pay a meaningful dividend and should not be held primarily for income.

For long-horizon retirement investors, Zoetis Inc.

(ZTS) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0. 90), 2. 3% yield, +107. 3% 10Y return). Repligen Corporation (RGEN) carries a higher beta of 1. 76 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (ZTS: +107. 3%, RGEN: +369. 1%), 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 Healthcare sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both.

In terms of investment character: CLGN is a small-cap quality compounder stock; IDXX is a mid-cap quality compounder stock; ZTS is a mid-cap deep-value stock; RGEN is a small-cap high-growth stock. ZTS pays a dividend while CLGN, IDXX, RGEN 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.