Comprehensive Stock Comparison
Compare Silence Therapeutics plc (SLN) vs Alnylam Pharmaceuticals, Inc. (ALNY) 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 | SLN | 70.5% revenue growth vs ALNY's 65.2% |
| Quality / Margins | ALNY | 8.4% net margin vs SLN's -252.2% |
| Stability / Safety | SLN | Beta 0.39 vs ALNY's 0.88, lower leverage |
| Dividends | Tie | Neither pays a meaningful dividend |
| Momentum (1Y) | ALNY | +34.9% vs SLN's +20.9% |
| Efficiency (ROA) | ALNY | 6.3% ROA vs SLN's -42.7%, ROIC 19.1% vs -370.7% |
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
Silence Therapeutics is a biotechnology company developing RNA interference therapeutics that target disease-associated genes in the liver. It generates revenue primarily through research collaborations and licensing deals—notably with AstraZeneca—while advancing its own pipeline of siRNA candidates through clinical trials. The company's key advantage is its proprietary mRNAi GalNAc platform technology, which enables precise targeting of liver-expressed genes with enhanced potency and durability.
Alnylam Pharmaceuticals is a biopharmaceutical company that develops and commercializes RNA interference (RNAi) therapeutics for rare genetic diseases. It generates revenue primarily from sales of its approved RNAi drugs — ONPATTRO, GIVLAARI, OXLUMO, and others — targeting conditions like hereditary transthyretin amyloidosis, acute hepatic porphyria, and primary hyperoxaluria. The company's key advantage is its pioneering RNAi technology platform and intellectual property estate, which creates a significant barrier to entry in the RNAi therapeutics space.
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
ALNY leads in 3 of 6 categories (Financial Metrics, Profitability & Efficiency). SLN leads in 2 (Valuation Metrics, Risk & Volatility).
Financial Metrics (TTM)
ALNY is the larger business by revenue, generating $3.7B annually — 149.4x SLN's $25M. ALNY is the more profitable business, keeping 8.4% of every revenue dollar as net income compared to SLN's -2.5%. On growth, ALNY holds the edge at +84.9% YoY revenue growth, suggesting stronger near-term business momentum.
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| RevenueTrailing 12 months | $25M | $3.7B |
| EBITDAEarnings before interest/tax | -$81M | $557M |
| Net IncomeAfter-tax profit | -$63M | $314M |
| Free Cash FlowCash after capex | -$70M | $465M |
| Gross MarginGross profit ÷ Revenue | +92.7% | +81.8% |
| Operating MarginEBIT ÷ Revenue | -3.3% | +13.5% |
| Net MarginNet income ÷ Revenue | -2.5% | +8.4% |
| FCF MarginFCF ÷ Revenue | -2.8% | +12.5% |
| Rev. Growth (YoY)Latest quarter vs prior year | -86.1% | +84.9% |
| EPS Growth (YoY)Latest quarter vs prior year | +22.8% | +3.1% |
Valuation Metrics
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| Market CapShares × price | $257M | $44.1B |
| Enterprise ValueMkt cap + debt − cash | $94M | $45.4B |
| Trailing P/EPrice ÷ TTM EPS | -1.71x | 142.88x |
| Forward P/EPrice ÷ next-FY EPS est. | — | 48.96x |
| PEG RatioP/E ÷ EPS growth rate | — | — |
| EV / EBITDAEnterprise value multiple | — | 81.44x |
| Price / SalesMarket cap ÷ Revenue | 4.42x | 11.87x |
| Price / BookPrice ÷ Book value/share | 0.47x | 56.82x |
| Price / FCFMarket cap ÷ FCF | — | 94.70x |
Profitability & Efficiency
ALNY delivers a 39.8% return on equity — every $100 of shareholder capital generates $40 in annual profit, vs $-85 for SLN. SLN carries lower financial leverage with a 0.00x debt-to-equity ratio, signaling a more conservative balance sheet compared to ALNY's 3.76x. On the Piotroski fundamental quality scale (0–9), ALNY scores 6/9 vs SLN's 5/9, reflecting solid financial health.
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| ROE (TTM)Return on equity | -84.6% | +39.8% |
| ROA (TTM)Return on assets | -42.7% | +6.3% |
| ROICReturn on invested capital | -3.7% | +19.1% |
| ROCEReturn on capital employed | -44.8% | +15.3% |
| Piotroski ScoreFundamental quality 0–9 | 5 | 6 |
| Debt / EquityFinancial leverage | 0.00x | 3.76x |
| Net DebtTotal debt minus cash | -$121M | $1.3B |
| Cash & Equiv.Liquid assets | $121M | $1.7B |
| Total DebtShort + long-term debt | $117,000 | $3.0B |
| Interest CoverageEBIT ÷ Interest expense | — | 7.20x |
Total Returns (with DRIP)
A $10,000 investment in ALNY five years ago would be worth $22,381 today (with dividends reinvested), compared to $2,154 for SLN. Over the past 12 months, ALNY leads with a +34.9% total return vs SLN's +20.9%. The 3-year compound annual growth rate (CAGR) favors ALNY at 20.3% vs SLN's -22.6% — a key indicator of consistent wealth creation.
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| YTD ReturnYear-to-date | -11.5% | -16.8% |
| 1-Year ReturnPast 12 months | +20.9% | +34.9% |
| 3-Year ReturnCumulative with dividends | -53.6% | +73.9% |
| 5-Year ReturnCumulative with dividends | -78.5% | +123.8% |
| 10-Year ReturnCumulative with dividends | -72.1% | +468.4% |
| CAGR (3Y)Annualised 3-year return | -22.6% | +20.3% |
Risk & Volatility
SLN is the less volatile stock with a 0.39 beta — it tends to amplify market swings less than ALNY's 0.88 beta. A beta below 1.0 means the stock typically moves less than the S&P 500.
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| Beta (5Y)Sensitivity to S&P 500 | 0.39x | 0.88x |
| 52-Week HighHighest price in past year | $7.78 | $495.55 |
| 52-Week LowLowest price in past year | $1.97 | $205.87 |
| % of 52W HighCurrent price vs 52-week peak | +69.9% | +67.2% |
| RSI (14)Momentum oscillator 0–100 | 58.7 | 43.8 |
| Avg Volume (50D)Average daily shares traded | 239K | 1.2M |
Analyst Outlook
Wall Street rates SLN as "Buy" and ALNY as "Buy". Consensus price targets imply 947.8% upside for SLN (target: $57) vs 38.5% for ALNY (target: $461).
| Metric | SLNSilence Therapeut… | ALNYAlnylam Pharmaceu… |
|---|---|---|
| Analyst RatingConsensus buy/hold/sell | Buy | Buy |
| Price TargetConsensus 12-month target | $57.00 | $461.06 |
| # AnalystsCovering analysts | 5 | 51 |
| Dividend YieldAnnual dividend ÷ price | — | — |
| Dividend StreakConsecutive years of raises | — | — |
| Dividend / ShareAnnual DPS | — | — |
| Buyback YieldShare repurchases ÷ mkt cap | 0.0% | 0.0% |
Historical Charts
Charts are rendered on first load. Hover for details.
Chart 1Total Return — 5 Years (Rebased to 100)
| Stock | Sep 20 | Feb 26 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | 100 | 25.13 | -74.9% |
| Alnylam Pharmaceuti… (ALNY) | 100 | 235.92 | +135.9% |
Alnylam Pharmaceuti… (ALNY) returned +124% over 5 years vs Silence Therapeutic… (SLN)'s -78%. A $10,000 investment in ALNY 5 years ago would be worth $22,381 today (including dividends reinvested).
Chart 2Revenue Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | $770000.00 | $43M | +5517.9% |
| Alnylam Pharmaceuti… (ALNY) | $47M | $3.7B | +7775.4% |
Alnylam Pharmaceuticals, Inc.'s revenue grew from $47M (2016) to $3.7B (2025) — a 62.4% CAGR.
Chart 3Net Margin Trend — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | -11.0% | -104.7% | -855.6% |
| Alnylam Pharmaceuti… (ALNY) | -8.7% | 8.4% | +197.1% |
Alnylam Pharmaceuticals, Inc.'s net margin went from -9% (2016) to 8% (2025).
Chart 4EPS Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | -0.4 | -2.37 | -492.5% |
| Alnylam Pharmaceuti… (ALNY) | -4.79 | 2.33 | +148.6% |
Alnylam Pharmaceuticals, Inc.'s EPS grew from $-4.79 (2016) to $2.33 (2025).
Chart 5Free Cash Flow — 5 Years
Silence Therapeutics plc generated $-68M FCF in 2024 (-1019% vs 2021). Alnylam Pharmaceuticals, Inc. generated $465M FCF in 2025 (+165% vs 2021).
SLN vs ALNY: Frequently Asked Questions
8 questions · data-driven answers · updated daily
01Is SLN or ALNY a better buy right now?
Alnylam Pharmaceuticals, Inc. (ALNY) offers the better valuation at 142.9x trailing P/E (49.0x forward), making it the more compelling value choice. Analysts rate Silence Therapeutics plc (SLN) a "Buy" — based on 5 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 is the better long-term investment — SLN or ALNY?
Over the past 5 years, Alnylam Pharmaceuticals, Inc. (ALNY) delivered a total return of +123.8%, compared to -78.5% for Silence Therapeutics plc (SLN). A $10,000 investment in ALNY five years ago would be worth approximately $22K today (assuming dividends reinvested). Over 10 years, the gap is even starker: ALNY returned +468.4% versus SLN's -72.1%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.
03Which is safer — SLN or ALNY?
By beta (market sensitivity over 5 years), Silence Therapeutics plc (SLN) is the lower-risk stock at 0.39β versus Alnylam Pharmaceuticals, Inc.'s 0.88β — meaning ALNY is approximately 126% more volatile than SLN relative to the S&P 500. On balance sheet safety, Silence Therapeutics plc (SLN) carries a lower debt/equity ratio of 0% versus 4% for Alnylam Pharmaceuticals, Inc. — giving it more financial flexibility in a downturn.
04Which has better profit margins — SLN or ALNY?
Alnylam Pharmaceuticals, Inc. (ALNY) is the more profitable company, earning 8.4% net margin versus -104.7% for Silence Therapeutics plc — meaning it keeps 8.4% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: ALNY leads at 13.5% versus -146.4% for SLN. At the gross margin level — before operating expenses — ALNY leads at 81.8%, 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.
05Is SLN or ALNY more undervalued right now?
Analyst consensus price targets imply the most upside for SLN: 947.8% to $57.00.
06Which pays a better dividend — SLN or ALNY?
None of the stocks in this comparison currently pay a material dividend. All are effectively zero-yield and should be held for capital appreciation rather than income.
07Is SLN or ALNY better for a retirement portfolio?
For long-horizon retirement investors, Silence Therapeutics plc (SLN) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0.39)). Both have compounded well over 10 years (SLN: -72.1%, ALNY: +468.4%), 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.
08What are the main differences between SLN and ALNY?
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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