Comprehensive Stock Comparison
Compare Spero Therapeutics, Inc. (SPRO) vs Regeneron Pharmaceuticals, Inc. (REGN) Stock
Analyze side-by-side fundamentals, valuation, growth, and profitability to decide which stock is the better buy.
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Quick Verdict
| Category | Winner | Why |
|---|---|---|
| Growth | REGN | 1.0% revenue growth vs SPRO's -53.8% |
| Value | SPRO | Lower P/E (3.2x vs 17.3x) |
| Quality / Margins | REGN | 31.4% net margin vs SPRO's -122.6% |
| Stability / Safety | REGN | Beta 0.58 vs SPRO's 0.86, lower leverage |
| Dividends | REGN | 0.4% yield; 1-year raise streak; SPRO pays no meaningful dividend |
| Momentum (1Y) | SPRO | +179.8% vs REGN's +12.4% |
| Efficiency (ROA) | REGN | 11.1% ROA vs SPRO's -80.9%, ROIC 12.4% vs -327.2% |
Who Each Stock Is For
Income & stability
Growth exposure
Long-term compounding (10Y)
Sleep-well-at-night portfolio
Defensive / Recession hedge
Business Model
What each company does and how it makes money
Spero Therapeutics is a clinical-stage biopharmaceutical company developing novel antibiotics to treat multi-drug resistant bacterial infections and rare diseases. It generates revenue primarily through strategic partnerships and licensing agreements — including deals with Meiji Seika Pharma, Everest Medicines, and the Gates Medical Research Institute — while advancing its pipeline toward commercialization. The company's competitive advantage lies in its focus on addressing urgent unmet medical needs in antimicrobial resistance with innovative oral and IV antibiotic candidates that target difficult-to-treat infections.
Regeneron Pharmaceuticals is a biotechnology company that discovers, develops, and commercializes innovative medicines for serious diseases. It generates revenue primarily from sales of its flagship products — EYLEA for eye diseases (~60% of revenue) and Dupixent for inflammatory conditions (~30%) — with additional income from collaborations and royalties. The company's competitive advantage lies in its proprietary VelocImmune technology platform for creating human antibodies and its deep expertise in genetic research, which enables rapid drug discovery and development.
Revenue Breakdown by Segment
How each company's revenue is distributed across its business units
Financial Metrics Comparison
Side-by-side fundamentals across 2 stocks. BestLagging
Financial Scorecard
REGN leads in 3 of 6 categories (Financial Metrics, Profitability & Efficiency). SPRO leads in 1 (Valuation Metrics). 1 tied.
Financial Metrics (TTM)
REGN is the larger business by revenue, generating $14.3B annually — 401.0x SPRO's $36M. REGN is the more profitable business, keeping 31.4% of every revenue dollar as net income compared to SPRO's -122.6%. On growth, REGN holds the edge at +2.5% YoY revenue growth, suggesting stronger near-term business momentum.
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| RevenueTrailing 12 months | $36M | $14.3B |
| EBITDAEarnings before interest/tax | -$45M | $4.2B |
| Net IncomeAfter-tax profit | -$44M | $4.5B |
| Free Cash FlowCash after capex | -$28M | $3.2B |
| Gross MarginGross profit ÷ Revenue | -2.0% | +86.3% |
| Operating MarginEBIT ÷ Revenue | -130.9% | +25.7% |
| Net MarginNet income ÷ Revenue | -122.6% | +31.4% |
| FCF MarginFCF ÷ Revenue | -77.4% | +22.0% |
| Rev. Growth (YoY)Latest quarter vs prior year | -77.4% | +2.5% |
| EPS Growth (YoY)Latest quarter vs prior year | +59.4% | -2.5% |
Valuation Metrics
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| Market CapShares × price | $122M | $107.6B |
| Enterprise ValueMkt cap + debt − cash | $74M | $91.4B |
| Trailing P/EPrice ÷ TTM EPS | -1.71x | 18.84x |
| Forward P/EPrice ÷ next-FY EPS est. | 3.24x | 17.25x |
| PEG RatioP/E ÷ EPS growth rate | — | 2.98x |
| EV / EBITDAEnterprise value multiple | — | 21.64x |
| Price / SalesMarket cap ÷ Revenue | 2.55x | 7.50x |
| Price / BookPrice ÷ Book value/share | 2.54x | 2.72x |
| Price / FCFMarket cap ÷ FCF | — | 26.36x |
Profitability & Efficiency
REGN delivers a 14.4% return on equity — every $100 of shareholder capital generates $14 in annual profit, vs $-165 for SPRO. REGN carries lower financial leverage with a 0.09x debt-to-equity ratio, signaling a more conservative balance sheet compared to SPRO's 0.09x. On the Piotroski fundamental quality scale (0–9), REGN scores 7/9 vs SPRO's 1/9, reflecting strong financial health.
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| ROE (TTM)Return on equity | -165.5% | +14.4% |
| ROA (TTM)Return on assets | -80.9% | +11.1% |
| ROICReturn on invested capital | -3.3% | +12.4% |
| ROCEReturn on capital employed | -71.0% | +10.8% |
| Piotroski ScoreFundamental quality 0–9 | 1 | 7 |
| Debt / EquityFinancial leverage | 0.09x | 0.09x |
| Net DebtTotal debt minus cash | -$49M | -$16.2B |
| Cash & Equiv.Liquid assets | $53M | $18.9B |
| Total DebtShort + long-term debt | $4M | $2.7B |
| Interest CoverageEBIT ÷ Interest expense | — | 120.42x |
Total Returns (with DRIP)
A $10,000 investment in REGN five years ago would be worth $16,977 today (with dividends reinvested), compared to $1,154 for SPRO. Over the past 12 months, SPRO leads with a +179.8% total return vs REGN's +12.4%. The 3-year compound annual growth rate (CAGR) favors SPRO at 13.6% vs REGN's 1.1% — a key indicator of consistent wealth creation.
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| YTD ReturnYear-to-date | -7.7% | +0.8% |
| 1-Year ReturnPast 12 months | +179.8% | +12.4% |
| 3-Year ReturnCumulative with dividends | +46.6% | +3.4% |
| 5-Year ReturnCumulative with dividends | -88.5% | +69.8% |
| 10-Year ReturnCumulative with dividends | -81.1% | +104.7% |
| CAGR (3Y)Annualised 3-year return | +13.6% | +1.1% |
Risk & Volatility
REGN is the less volatile stock with a 0.58 beta — it tends to amplify market swings less than SPRO's 0.86 beta. A beta below 1.0 means the stock typically moves less than the S&P 500. REGN currently trades 95.2% from its 52-week high vs SPRO's 67.4% drawdown — a narrower gap to the peak suggests stronger recent price momentum.
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| Beta (5Y)Sensitivity to S&P 500 | 0.86x | 0.58x |
| 52-Week HighHighest price in past year | $3.22 | $821.11 |
| 52-Week LowLowest price in past year | $0.51 | $476.49 |
| % of 52W HighCurrent price vs 52-week peak | +67.4% | +95.2% |
| RSI (14)Momentum oscillator 0–100 | 40.1 | 49.1 |
| Avg Volume (50D)Average daily shares traded | 237K | 687K |
Analyst Outlook
Wall Street rates SPRO as "Buy" and REGN as "Buy". REGN is the only dividend payer here at 0.44% yield — a key consideration for income-focused portfolios.
| Metric | SPROSpero Therapeutic… | REGNRegeneron Pharmac… |
|---|---|---|
| Analyst RatingConsensus buy/hold/sell | Buy | Buy |
| Price TargetConsensus 12-month target | — | $857.17 |
| # AnalystsCovering analysts | 13 | 48 |
| Dividend YieldAnnual dividend ÷ price | — | +0.4% |
| Dividend StreakConsecutive years of raises | — | 1 |
| Dividend / ShareAnnual DPS | — | $3.41 |
| Buyback YieldShare repurchases ÷ mkt cap | 0.0% | +3.2% |
Historical Charts
Charts are rendered on first load. Hover for details.
Chart 1Total Return — 5 Years (Rebased to 100)
| Stock | Mar 20 | Feb 26 | Change |
|---|---|---|---|
| Spero Therapeutics,… (SPRO) | 100 | 24.48 | -75.5% |
| Regeneron Pharmaceu… (REGN) | 100 | 163.58 | +63.6% |
Regeneron Pharmaceu… (REGN) returned +70% over 5 years vs Spero Therapeutics,… (SPRO)'s -88%. A $10,000 investment in REGN 5 years ago would be worth $16,977 today (including dividends reinvested).
Chart 2Revenue Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Spero Therapeutics,… (SPRO) | $335000.00 | $48M | +14221.5% |
| Regeneron Pharmaceu… (REGN) | $4.9B | $14.3B | +195.1% |
Regeneron Pharmaceuticals, Inc.'s revenue grew from $4.9B (2016) to $14.3B (2025) — a 12.8% CAGR.
Chart 3Net Margin Trend — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Spero Therapeutics,… (SPRO) | -76.1% | -142.9% | -87.8% |
| Regeneron Pharmaceu… (REGN) | 18.4% | 31.4% | +70.5% |
Regeneron Pharmaceuticals, Inc.'s net margin went from 18% (2016) to 31% (2025).
Chart 4P/E Ratio History — 9 Years
| Stock | 2017 | 2025 | Change |
|---|---|---|---|
| Regeneron Pharmaceu… (REGN) | 36.4 | 18.6 | -48.9% |
Regeneron Pharmaceuticals, Inc. has traded in a 9x–36x P/E range over 9 years; current trailing P/E is ~19x.
Chart 5EPS Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Spero Therapeutics,… (SPRO) | -3.86 | -1.27 | +67.1% |
| Regeneron Pharmaceu… (REGN) | 7.7 | 41.48 | +438.7% |
Regeneron Pharmaceuticals, Inc.'s EPS grew from $7.70 (2016) to $41.48 (2025) — a 21% CAGR.
Chart 6Free Cash Flow — 5 Years
Spero Therapeutics, Inc. generated $-23M FCF in 2024. Regeneron Pharmaceuticals, Inc. generated $4B FCF in 2025 (-38% vs 2021).
SPRO vs REGN: Frequently Asked Questions
9 questions · data-driven answers · updated daily
01Is SPRO or REGN a better buy right now?
Regeneron Pharmaceuticals, Inc. (REGN) offers the better valuation at 18.8x trailing P/E (17.3x forward), making it the more compelling value choice. Analysts rate Spero Therapeutics, Inc. (SPRO) a "Buy" — based on 13 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.
02Which has the better valuation — SPRO or REGN?
On forward P/E, Spero Therapeutics, Inc. is actually cheaper at 3.2x — notably different from the trailing picture, reflecting expected earnings growth.
03Which is the better long-term investment — SPRO or REGN?
Over the past 5 years, Regeneron Pharmaceuticals, Inc. (REGN) delivered a total return of +69.8%, compared to -88.5% for Spero Therapeutics, Inc. (SPRO). A $10,000 investment in REGN five years ago would be worth approximately $17K today (assuming dividends reinvested). Over 10 years, the gap is even starker: REGN returned +104.7% versus SPRO's -81.1%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.
04Which is safer — SPRO or REGN?
By beta (market sensitivity over 5 years), Regeneron Pharmaceuticals, Inc. (REGN) is the lower-risk stock at 0.58β versus Spero Therapeutics, Inc.'s 0.86β — meaning SPRO is approximately 50% more volatile than REGN relative to the S&P 500. On balance sheet safety, Regeneron Pharmaceuticals, Inc. (REGN) carries a lower debt/equity ratio of 9% versus 9% for Spero Therapeutics, Inc. — giving it more financial flexibility in a downturn.
05Which has better profit margins — SPRO or REGN?
Regeneron Pharmaceuticals, Inc. (REGN) is the more profitable company, earning 31.4% net margin versus -142.9% for Spero Therapeutics, Inc. — meaning it keeps 31.4% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: REGN leads at 25.7% versus -152.9% for SPRO. At the gross margin level — before operating expenses — REGN leads at 86.3%, 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.
06Is SPRO or REGN more undervalued right now?
On forward earnings alone, Spero Therapeutics, Inc. (SPRO) trades at 3.2x forward P/E versus 17.3x for Regeneron Pharmaceuticals, Inc. — 14.0x cheaper on a one-year earnings basis.
07Which pays a better dividend — SPRO or REGN?
In this comparison, REGN (0.4% yield) pays a dividend. SPRO does not pay a meaningful dividend and should not be held primarily for income.
08Is SPRO or REGN better for a retirement portfolio?
For long-horizon retirement investors, Regeneron Pharmaceuticals, Inc. (REGN) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0.58), +104.7% 10Y return). Both have compounded well over 10 years (REGN: +104.7%, SPRO: -81.1%), 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.
09What are the main differences between SPRO and REGN?
Both stocks operate in the Healthcare sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both. 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.
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