Spero Therapeutics

SPRO

Biotechnology · Healthcare

Price

$1.58

+0.01 (+0.64%)

Market Cap

$91.5M

Exchange

NASDAQ

Winston Score

Winston is serious

Mixed quality — meaningful strengths and weaknesses.

Share count rising — dilution

+91.1% over 4y

The company has issued more shares over this period, which dilutes each existing shareholder’s stake.

Diluted shares outstanding: 30.9M (2021) → 59.0M (2025)

Spero Therapeutics, Inc., a clinical-stage biopharmaceutical company, focuses on identifying, developing, and commercializing treatments for multi-drug resistant (MDR) bacterial infections and rare diseases in the United States. The company's product candidates include tebipenem pivoxil hydrobromide (HBr), an oral carbapenem-class antibiotic to treat complicated urinary tract infections, including pyelonephritis for adults; SPR206, a direct acting IV-administered agent to treat MDR Gram-negative

Winston Score History

Growth Profile

For growth stock investors

When traditional metrics don't capture the full picture, these are the signals growth stock investors use instead.

Revenue Growth

-95.6% YoY

YoY Growth Rate

Revenue declining

EPS Growth

+48.0% YoY

YoY Growth Rate

EPS growth accelerating

R&D Spend

$38M/ year

↓ Declining (-60% vs prior year)

64.5% of revenue

3.6x the sector average (18%)

R&D spend declining — could signal cost-cutting or efficiency

Insider Activity

19.7%ownership

↑ Rising

Insiders increasing their stake — aligned with shareholders

Cash Position

Cash flow positive

$56M cash & investments

Company generates more cash than it spends — no dilution risk from fundraising

Revenue declining

Spero Therapeutics's revenue is actually shrinking. In a growth stock, that removes the core investment thesis. The low Winston Score here may be warranted — unless there's a turnaround story.

The Winston Score above measures business quality today. Growth stocks often score lower because they invest in the future rather than maximising current profits. These metrics show what matters most for evaluating that future.

Score breakdown

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Quality

Gross Margin

0.0%

Thin — 0.0% gross margin

Operating Margin

-2921.7%

Losing money on operations — -2921.7%

ROCE

-13.6%

Weak — -13.6% return on capital

Negative ROIC means the business is losing money on every dollar invested in it.

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Growth

Sales YoY

+22.8%

Fast-growing sales (22.8% YoY)

EPS YoY

N/A

Data not available

EPS Consistency

2/8 quarters

Earnings rarely grow — volatile business

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Cash Flow

Cash Conversion

32%

Weak — only 32% of profit becomes cash

FCF Margin

13.2%

Converts sales into free cash efficiently (13.2%)

FCF margin between 10% and 20%. Every $100 in sales becomes $10 to $20 in real cash.

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Stability

Debt / Equity

0.05

Conservative — low debt load (0.05)

Interest Cover

100.00x

—

Comfortably covers interest (100.0x)

Interest coverage above 8. Profits cover interest many times over.

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Valuation

P/E Ratio (TTM)

5.9x

Attractive valuation — P/E 5.9

P/E under 10. The price tag is small relative to last year's profit.

P/E vs Forward

+2.6

GROWING

Earnings expected to grow — slightly cheaper on forward P/E

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Dividends

Not applicable for this business.

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