Comprehensive Stock Comparison
Compare Silence Therapeutics plc (SLN) vs Ionis Pharmaceuticals, Inc. (IONS) 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 IONS's 33.9% |
| Quality / Margins | IONS | -40.4% net margin vs SLN's -252.2% |
| Stability / Safety | SLN | Beta 0.39 vs IONS's 0.68, lower leverage |
| Dividends | Tie | Neither pays a meaningful dividend |
| Momentum (1Y) | IONS | +144.5% vs SLN's +20.9% |
| Efficiency (ROA) | IONS | -10.8% ROA vs SLN's -42.7%, ROIC -12.2% 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.
Ionis Pharmaceuticals is a biotech company that discovers and develops RNA-targeted therapeutics for rare diseases and other serious conditions. It generates revenue primarily through royalties from partnered drugs like SPINRAZA for spinal muscular atrophy — which contributed over 70% of total revenue in recent years — plus milestone payments and research funding from pharmaceutical partners. Its key competitive advantage is its proprietary antisense technology platform, which enables precise targeting of disease-causing RNA and has produced multiple FDA-approved therapies.
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
IONS leads in 2 of 6 categories (Financial Metrics, Total Returns). SLN leads in 1 (Valuation Metrics). 2 tied.
Financial Metrics (TTM)
IONS is the larger business by revenue, generating $943M annually — 38.0x SLN's $25M. Profitability is closely matched — net margins range from -40.4% (IONS) to -2.5% (SLN). On growth, IONS holds the edge at -10.4% YoY revenue growth, suggesting stronger near-term business momentum.
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| RevenueTrailing 12 months | $25M | $943M |
| EBITDAEarnings before interest/tax | -$81M | -$367M |
| Net IncomeAfter-tax profit | -$63M | -$381M |
| Free Cash FlowCash after capex | -$70M | $162.9B |
| Gross MarginGross profit ÷ Revenue | +92.7% | +98.3% |
| Operating MarginEBIT ÷ Revenue | -3.3% | -40.5% |
| Net MarginNet income ÷ Revenue | -2.5% | -40.4% |
| FCF MarginFCF ÷ Revenue | -2.8% | +172.6% |
| Rev. Growth (YoY)Latest quarter vs prior year | -86.1% | -10.4% |
| EPS Growth (YoY)Latest quarter vs prior year | +22.8% | -113.6% |
Valuation Metrics
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| Market CapShares × price | $257M | $13.3B |
| Enterprise ValueMkt cap + debt − cash | $94M | $15.7B |
| Trailing P/EPrice ÷ TTM EPS | -1.71x | -34.10x |
| Forward P/EPrice ÷ next-FY EPS est. | — | — |
| PEG RatioP/E ÷ EPS growth rate | — | — |
| EV / EBITDAEnterprise value multiple | — | — |
| Price / SalesMarket cap ÷ Revenue | 4.42x | 14.04x |
| Price / BookPrice ÷ Book value/share | 0.47x | 26.55x |
| Price / FCFMarket cap ÷ FCF | — | — |
Profitability & Efficiency
IONS delivers a -77.9% return on equity — every $100 of shareholder capital generates $-78 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 IONS's 5.78x. On the Piotroski fundamental quality scale (0–9), SLN scores 5/9 vs IONS's 3/9, reflecting solid financial health.
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| ROE (TTM)Return on equity | -84.6% | -77.9% |
| ROA (TTM)Return on assets | -42.7% | -10.8% |
| ROICReturn on invested capital | -3.7% | -12.2% |
| ROCEReturn on capital employed | -44.8% | -16.3% |
| Piotroski ScoreFundamental quality 0–9 | 5 | 3 |
| Debt / EquityFinancial leverage | 0.00x | 5.78x |
| Net DebtTotal debt minus cash | -$121M | $2.5B |
| Cash & Equiv.Liquid assets | $121M | $372M |
| Total DebtShort + long-term debt | $117,000 | $2.8B |
| Interest CoverageEBIT ÷ Interest expense | — | -3.53x |
Total Returns (with DRIP)
A $10,000 investment in IONS five years ago would be worth $15,014 today (with dividends reinvested), compared to $2,154 for SLN. Over the past 12 months, IONS leads with a +144.5% total return vs SLN's +20.9%. The 3-year compound annual growth rate (CAGR) favors IONS at 31.2% vs SLN's -22.6% — a key indicator of consistent wealth creation.
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| YTD ReturnYear-to-date | -11.5% | +1.9% |
| 1-Year ReturnPast 12 months | +20.9% | +144.5% |
| 3-Year ReturnCumulative with dividends | -53.6% | +126.0% |
| 5-Year ReturnCumulative with dividends | -78.5% | +50.1% |
| 10-Year ReturnCumulative with dividends | -72.1% | +134.8% |
| CAGR (3Y)Annualised 3-year return | -22.6% | +31.2% |
Risk & Volatility
SLN is the less volatile stock with a 0.39 beta — it tends to amplify market swings less than IONS's 0.68 beta. A beta below 1.0 means the stock typically moves less than the S&P 500. IONS currently trades 93.6% from its 52-week high vs SLN's 69.9% drawdown — a narrower gap to the peak suggests stronger recent price momentum.
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| Beta (5Y)Sensitivity to S&P 500 | 0.39x | 0.68x |
| 52-Week HighHighest price in past year | $7.78 | $86.74 |
| 52-Week LowLowest price in past year | $1.97 | $23.95 |
| % of 52W HighCurrent price vs 52-week peak | +69.9% | +93.6% |
| RSI (14)Momentum oscillator 0–100 | 58.7 | 44.7 |
| Avg Volume (50D)Average daily shares traded | 239K | 1.7M |
Analyst Outlook
Wall Street rates SLN as "Buy" and IONS as "Buy". Consensus price targets imply 947.8% upside for SLN (target: $57) vs 9.8% for IONS (target: $89).
| Metric | SLNSilence Therapeut… | IONSIonis Pharmaceuti… |
|---|---|---|
| Analyst RatingConsensus buy/hold/sell | Buy | Buy |
| Price TargetConsensus 12-month target | $57.00 | $89.13 |
| # AnalystsCovering analysts | 5 | 32 |
| 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% |
| Ionis Pharmaceutica… (IONS) | 100 | 173.93 | +73.9% |
Ionis Pharmaceutica… (IONS) returned +50% over 5 years vs Silence Therapeutic… (SLN)'s -78%. A $10,000 investment in IONS 5 years ago would be worth $15,014 today (including dividends reinvested).
Chart 2Revenue Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | $770000.00 | $43M | +5517.9% |
| Ionis Pharmaceutica… (IONS) | $373M | $944M | +153.2% |
Ionis Pharmaceuticals, Inc.'s revenue grew from $373M (2016) to $944M (2025) — a 10.9% CAGR.
Chart 3Net Margin Trend — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | -11.0% | -104.7% | -855.6% |
| Ionis Pharmaceutica… (IONS) | -16.2% | -40.4% | -149.1% |
Ionis Pharmaceuticals, Inc.'s net margin went from -16% (2016) to -40% (2025).
Chart 4EPS Growth — 10 Years
| Stock | 2016 | 2025 | Change |
|---|---|---|---|
| Silence Therapeutic… (SLN) | -0.4 | -2.37 | -492.5% |
| Ionis Pharmaceutica… (IONS) | -0.72 | -2.38 | -230.6% |
Ionis Pharmaceuticals, Inc.'s EPS grew from $-0.72 (2016) to $-2.38 (2025).
Chart 5Free Cash Flow — 5 Years
Silence Therapeutics plc generated $-68M FCF in 2024 (-1019% vs 2021). Ionis Pharmaceuticals, Inc. generated $-320M FCF in 2025 (-2581% vs 2021).
SLN vs IONS: Frequently Asked Questions
7 questions · data-driven answers · updated daily
01Is SLN or IONS a better buy right now?
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 IONS?
Over the past 5 years, Ionis Pharmaceuticals, Inc. (IONS) delivered a total return of +50.1%, compared to -78.5% for Silence Therapeutics plc (SLN). A $10,000 investment in IONS five years ago would be worth approximately $15K today (assuming dividends reinvested). Over 10 years, the gap is even starker: IONS returned +134.8% 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 IONS?
By beta (market sensitivity over 5 years), Silence Therapeutics plc (SLN) is the lower-risk stock at 0.39β versus Ionis Pharmaceuticals, Inc.'s 0.68β — meaning IONS is approximately 76% 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 6% for Ionis Pharmaceuticals, Inc. — giving it more financial flexibility in a downturn.
04Which has better profit margins — SLN or IONS?
Ionis Pharmaceuticals, Inc. (IONS) is the more profitable company, earning -40.4% net margin versus -104.7% for Silence Therapeutics plc — meaning it keeps -40.4% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: IONS leads at -40.5% versus -146.4% for SLN. At the gross margin level — before operating expenses — IONS leads at 98.3%, 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.
05Which pays a better dividend — SLN or IONS?
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.
06Is SLN or IONS 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%, IONS: +134.8%), 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.
07What are the main differences between SLN and IONS?
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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