ACIU vs BIIB

For growth investors, Biogen Inc.

(BIIB) is the stronger pick with 1. 4% revenue growth year-over-year, versus -86. 9% for AC Immune S. A. (ACIU). Biogen Inc. (BIIB) offers the better valuation at 21. 7x trailing P/E (13. 0x forward), making it the more compelling value choice. Analysts rate AC Immune S. A. (ACIU) a "Buy" — based on 9 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.

Over the past 5 years, Biogen Inc.

(BIIB) delivered a total return of -30. 2%, compared to -52. 4% for AC Immune S. A. (ACIU). Over 10 years, the gap is even starker: BIIB returned -28. 4% versus ACIU's -81. 7%. 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), Biogen Inc.

(BIIB) is the lower-risk stock at 0. 60β versus AC Immune S. A. 's 1. 54β — meaning ACIU is approximately 155% more volatile than BIIB relative to the S&P 500. On balance sheet safety, AC Immune S. A. (ACIU) carries a lower debt/equity ratio of 10% versus 38% for Biogen Inc. — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), Biogen Inc.

(BIIB) is pulling ahead at 1. 4% versus -86. 9% for AC Immune S. A. (ACIU). On earnings-per-share growth, the picture is similar: Biogen Inc. grew EPS -21. 1% year-over-year, compared to -37. 3% for AC Immune S. A.. Over a 3-year CAGR, BIIB leads at -1. 2% 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.

Biogen Inc.

(BIIB) is the more profitable company, earning 13. 2% net margin versus -1971. 6% for AC Immune S. A. — meaning it keeps 13. 2% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: BIIB leads at 19. 1% versus -1927. 3% for ACIU. At the gross margin level — before operating expenses — ACIU leads at 100. 0%, 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.

Analyst consensus price targets imply the most upside for ACIU: 138.

9% to $7. 00.

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.

For long-horizon retirement investors, Biogen Inc.

(BIIB) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0. 60)). AC Immune S. A. (ACIU) carries a higher beta of 1. 54 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (BIIB: -28. 4%, ACIU: -81. 7%), 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.

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.