CLNE vs. VOO

Last updated Aug 1, 2026

CLNE (Clean Energy Fuels Corp.) is a stock, while VOO (Vanguard S&P 500 ETF) is S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, CLNE returned -3.46%/yr vs 15.14%/yr for VOO. Their 0.42 correlation means their historical movements had little consistent relationship.

Performance

CLNE vs. VOO - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Clean Energy Fuels Corp. (CLNE) and Vanguard S&P 500 ETF (VOO). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, CLNE achieves a -7.62% return, which is significantly lower than VOO's 10.16% return. Over the past 10 years, CLNE has underperformed VOO with an annualized return of -3.46%, while VOO has yielded a comparatively higher 15.14% annualized return.

CLNE

• 1D: 0.52%
• 1M: -5.37%
• 6M: -11.82%
• YTD: -7.62%
• 1Y: -1.52%
• 3Y*: -26.32%
• 5Y*: -23.72%
• 10Y*: -3.46%
• ALL TIME*: -9.06%

VOO

• 1D: 0.71%
• 1M: 0.26%
• 6M: 8.58%
• YTD: 10.16%
• 1Y: 21.58%
• 3Y*: 19.42%
• 5Y*: 12.83%
• 10Y*: 15.14%
• ALL TIME*: 14.78%

*Multi-year figures are annualized to reflect compound growth (CAGR)

Liquidity Comparison

Position	Avg. Volume Value (2W)	Avg. Volume Value (1M)	Avg. Volume Value (3M)
CLNE Clean Energy Fuels Corp.	$2.63M	$3.54M	$3.20M
VOO Vanguard S&P 500 ETF	$3.82B	$3.78B	$5.44B

CLNE vs. VOO - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
CLNE Clean Energy Fuels Corp.	-7.62%	-16.33%	-34.46%	-26.35%	-15.17%	-22.01%	235.90%	36.05%	-15.27%	-29.02%
VOO Vanguard S&P 500 ETF	10.16%	17.82%	24.98%	26.32%	-18.17%	28.79%	18.32%	31.37%	-4.50%	21.77%

Correlation

The correlation between CLNE and VOO is 0.10, meaning there was essentially no consistent relationship between their historical price movements. Each responded to its own set of market drivers.

	Correlation
Correlation (1Y) Focuses on recent behavior, but can change the most.	0.10
Correlation (3Y) Balances recent behavior with more history.	0.29
Correlation (5Y) Shows whether the relationship held over a longer period.	0.41
Correlation (10Y) Provides a long-term view across more market conditions.	0.39
Correlation (All Time) Calculated using the full available price history since Sep 9, 2010	0.42

Over the past year, the correlation between CLNE and VOO has dropped to 0.10 - well below their long-term average of 0.42, suggesting their price drivers have been diverging.

Return for Risk

CLNE vs. VOO — Risk / Return Rank

Compare historical risk-adjusted metric ranks over the past 12 months.

CLNE

CLNE Risk / Return Rank: 40
CLNE Sharpe Ratio Rank: 41
CLNE Sortino Ratio Rank: 40
CLNE Omega Ratio Rank: 40
CLNE Calmar Ratio Rank: 41
CLNE Martin Ratio Rank: 41

VOO

VOO Risk / Return Rank: 68
VOO Sharpe Ratio Rank: 68
VOO Sortino Ratio Rank: 65
VOO Omega Ratio Rank: 66
VOO Calmar Ratio Rank: 64
VOO Martin Ratio Rank: 76

The rank (0–100) uses a weighted average of the Sharpe, Sortino, Omega, Calmar, and Martin percentile ranks for the trailing 12 months. Higher means stronger historical risk-adjusted performance within the peer group.

CLNE vs. VOO - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Clean Energy Fuels Corp. (CLNE) and Vanguard S&P 500 ETF (VOO). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	CLNE	VOO	Difference
Sharpe ratio: Return per unit of total volatility	-0.08	1.53	-1.62
Sortino ratio: Return per unit of downside risk	0.27	2.13	-1.87
Omega ratio: Gain probability vs. loss probability	1.03	1.28	-0.24
Calmar ratio: Return relative to maximum drawdown	-0.10	2.21	-2.31
Martin ratio: Return relative to average drawdown	-0.18	9.44	-9.62

CLNE vs. VOO - Sharpe Ratio Comparison

The current CLNE Sharpe Ratio is -0.08, which is lower than the VOO Sharpe Ratio of 1.53. The chart below compares the historical Sharpe Ratios of CLNE and VOO, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

CLNE vs. VOO - Drawdown Comparison

The maximum CLNE drawdown since its inception was -95.48%, which is greater than VOO's maximum drawdown of -33.99%. Use the drawdown chart below to compare losses from any high point for CLNE and VOO.

Drawdown Indicators

	CLNE	VOO	Difference
Max Drawdown Largest peak-to-trough decline	-95.48%	-33.99%	-61.49%
Max Drawdown (1Y) Largest decline over 1 year	-43.46%	-8.90%	-34.56%
Max Drawdown (3Y) Largest decline over 3 years	-71.55%	-18.69%	-52.86%
Max Drawdown (5Y) Largest decline over 5 years	-86.16%	-24.52%	-61.64%
Max Drawdown (10Y) Largest decline over 10 years	-92.92%	-33.99%	-58.93%
Current Drawdown Current decline from peak	-91.89%	-1.38%	-90.51%
Average Drawdown Average peak-to-trough decline	-66.67%	-3.67%	-63.00%
Ulcer Index Depth and duration of drawdowns from previous peaks	24.30%	2.08%	+22.22%

Volatility

CLNE vs. VOO - Volatility Comparison

Clean Energy Fuels Corp. (CLNE) has a higher volatility of 15.17% compared to Vanguard S&P 500 ETF (VOO) at 3.54%. This indicates that CLNE's price experiences larger fluctuations and is considered to be riskier than VOO based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	CLNE	VOO	Difference
Volatility (1M) Calculated over the trailing 1-month period	15.17%	3.54%	+11.63%
Volatility (6M) Calculated over the trailing 6-month period	35.19%	10.10%	+25.09%
Volatility (1Y) Calculated over the trailing 1-year period	53.20%	12.82%	+40.38%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	63.64%	16.93%	+46.71%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	71.36%	18.01%	+53.35%

Dividends

CLNE vs. VOO - Dividend Comparison

CLNE has not paid dividends to shareholders, while VOO's dividend yield for the trailing twelve months is around 1.07%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CLNE Clean Energy Fuels Corp.	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
VOO Vanguard S&P 500 ETF	1.07%	1.13%	1.24%	1.46%	1.69%	1.25%	1.54%	1.88%	2.06%	1.78%	2.02%	2.10%

Frequently Asked Questions

Can I hold both CLNE and VOO in my portfolio?

CLNE and VOO have a correlation of 0.10, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, CLNE or VOO?

CLNE has higher volatility (15.17%) compared to VOO (3.54%). In terms of maximum drawdown, CLNE dropped -95.48% vs VOO's -33.99%.

Which has better risk-adjusted returns?

VOO currently has the higher Sharpe Ratio (1.53 vs -0.08), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.