ESS Tech

GWH

Electrical Equipment & Parts · Industrials

Price

$0.88

-0.01 (-0.60%)

Market Cap

$11.1M

Winston Score

Winston is serious

Below-average fundamentals — multiple weak pillars.

Share count falling — buybacks

−82.5% over 4y

The company has reduced its share count over this period, returning value to shareholders through buybacks.

Diluted shares outstanding: 83.3M (2021) → 14.6M (2025)

ESS Tech makes large batteries designed to store electricity for long periods of time — think 4 to 12 hours or more. Its main product is the Energy Warehouse, an iron-flow battery that uses iron, salt, and water instead of the lithium found in most batteries. The company sells to utilities, renewable energy developers, and commercial customers who need to store solar or wind power and release it when the grid needs it most.

ESS makes money by selling its battery systems directly to customers, typically through project-based contracts. The company operates primarily in the United States but is pursuing international markets as well. Its iron-flow chemistry is meant to be a safer, longer-lasting, and cheaper alternative to lithium-ion at large scale — but the company is still early-stage and losing significant money on every dollar of revenue it earns. The biggest risk is whether ESS can scale up manufacturing fast enough and cut costs before it runs out of cash.

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

-155.7% YoY

YoY Growth Rate

Revenue declining

EPS Growth

+39.1% YoY

YoY Growth Rate

EPS growth accelerating

R&D Spend

$8M/ year

↓ Declining (-30% vs prior year)

524.1% of revenue

131.0x the sector average (4%)

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

Insider Activity

59.0%ownership

→ Flat

Insiders holding steady — not selling despite ability to

Cash Runway

~1 months

$14M cash & investments

Quarterly Free Cash Flow

→ Burn rate stable

Short runway — potential dilution ahead through share issuance

Cash watch

ESS Tech has less than a year of cash at its current burn rate. Growth investors should watch for potential share dilution from future fundraising — that directly reduces your ownership.

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

Every number that matters to educated investors.

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Quality

Gross Margin

972.2%

Premium pricing power — 972.2% gross margin

Operating Margin

1019.3%

Excellent — 1019.3% operating margin

ROCE

-129.9%

Weak — -129.9% return on capital

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

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Growth

Sales YoY

-74.9%

Shrinking sales (-74.9% YoY)

EPS YoY

N/A

—

Data not available

EPS Consistency

0/8 quarters

Earnings rarely grow — volatile business

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Cash Flow

Cash Conversion

N/A

—

Data not available

FCF Margin

-4612.1%

Burning cash (-4612.1%)

Free cash flow is negative. They are burning cash, not generating it.

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Stability

Debt / Equity

0.45

Conservative — low debt load (0.45)

Interest Cover

N/A

Data not available

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Valuation

P/E Ratio (TTM)

N/M

—

Negative earnings — P/E not meaningful

P/E vs Forward

N/A

not available

Data not available

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Dividends

Not applicable for this business.

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