SPRO vs AGEN

For growth investors, Agenus Inc.

(AGEN) is the stronger pick with 10. 4% revenue growth year-over-year, versus -53. 8% for Spero Therapeutics, Inc. (SPRO). 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.

Over the past 5 years, Spero Therapeutics, Inc.

(SPRO) delivered a total return of -81. 3%, compared to -93. 9% for Agenus Inc. (AGEN). Over 10 years, the gap is even starker: SPRO returned -78. 2% versus AGEN's -94. 3%. 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), Spero Therapeutics, Inc.

(SPRO) is the lower-risk stock at 0. 90β versus Agenus Inc. 's 2. 72β — meaning AGEN is approximately 201% more volatile than SPRO relative to the S&P 500.

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

(AGEN) is pulling ahead at 10. 4% versus -53. 8% for Spero Therapeutics, Inc. (SPRO). On earnings-per-share growth, the picture is similar: Agenus Inc. grew EPS 100. 0% year-over-year, compared to -395. 3% for Spero Therapeutics, Inc.. Over a 3-year CAGR, SPRO leads at 150. 0% 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.

Agenus Inc.

(AGEN) is the more profitable company, earning 0. 1% net margin versus -142. 9% for Spero Therapeutics, Inc. — meaning it keeps 0. 1% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: AGEN leads at -18. 0% versus -152. 9% for SPRO. At the gross margin level — before operating expenses — AGEN leads at 90. 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.

On forward earnings alone, Agenus Inc.

(AGEN) trades at 1. 8x forward P/E versus 3. 7x for Spero Therapeutics, Inc. — 2. 0x cheaper on a one-year earnings basis.

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, Spero Therapeutics, Inc.

(SPRO) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0. 90)). Agenus Inc. (AGEN) carries a higher beta of 2. 72 — meaning larger drawdowns in market downturns, which matters significantly when you cannot wait years for a recovery. Both have compounded well over 10 years (SPRO: -78. 2%, AGEN: -94. 3%), 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.