WTM vs MKL vs ACGL

For growth investors, White Mountains Insurance Group, Ltd.

(WTM) is the stronger pick with 15. 0% revenue growth year-over-year, versus -1. 0% for Markel Corporation (MKL). White Mountains Insurance Group, Ltd. (WTM) offers the better valuation at 4. 9x trailing P/E (18. 5x forward), making it the more compelling value choice. Analysts rate Arch Capital Group Ltd. (ACGL) a "Buy" — based on 34 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, White Mountains Insurance Group, Ltd.

(WTM) is the cheapest at 4. 9x versus Markel Corporation at 10. 7x. On forward P/E, Arch Capital Group Ltd. is actually cheaper at 10. 0x — 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: Arch Capital Group Ltd. wins at 0. 35x versus White Mountains Insurance Group, Ltd. 's 1. 36x — a PEG below 1. 0 traditionally signals the market is underpricing earnings growth.

Over the past 5 years, Arch Capital Group Ltd.

(ACGL) delivered a total return of +147. 5%, compared to +49. 3% for Markel Corporation (MKL). Over 10 years, the gap is even starker: ACGL returned +321. 0% versus MKL's +90. 9%. 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), Arch Capital Group Ltd.

(ACGL) is the lower-risk stock at -0. 01β versus Markel Corporation's 0. 43β — meaning MKL is approximately -3870% more volatile than ACGL relative to the S&P 500. On balance sheet safety, Arch Capital Group Ltd. (ACGL) carries a lower debt/equity ratio of 11% versus 23% for Markel Corporation — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), White Mountains Insurance Group, Ltd.

(WTM) is pulling ahead at 15. 0% versus -1. 0% for Markel Corporation (MKL). On earnings-per-share growth, the picture is similar: White Mountains Insurance Group, Ltd. grew EPS 379. 1% year-over-year, compared to -15. 1% for Markel Corporation. Over a 3-year CAGR, WTM leads at 32. 7% 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.

White Mountains Insurance Group, Ltd.

(WTM) is the more profitable company, earning 40. 9% net margin versus 12. 7% for Markel Corporation — meaning it keeps 40. 9% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: WTM leads at 49. 1% versus 16. 5% for MKL. At the gross margin level — before operating expenses — MKL leads at 69. 4%, 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, Arch Capital Group Ltd. (ACGL) is the more undervalued stock at a PEG of 0. 35x versus White Mountains Insurance Group, Ltd. 's 1. 36x. A PEG below 1. 0 is traditionally considered the threshold for growth-adjusted undervaluation. On forward earnings alone, Arch Capital Group Ltd. (ACGL) trades at 10. 0x forward P/E versus 18. 5x for White Mountains Insurance Group, Ltd. — 8. 5x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for ACGL: 10. 9% to $104. 00.

In this comparison, MKL (2.

7% yield) pays a dividend. WTM, ACGL do not pay a meaningful dividend and should not be held primarily for income.

For long-horizon retirement investors, Arch Capital Group Ltd.

(ACGL) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β -0. 01), +321. 0% 10Y return). Both have compounded well over 10 years (ACGL: +321. 0%, WTM: +160. 8%), 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 Financial Services sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both.

MKL pays a dividend while WTM, ACGL 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.