ATO vs. SPY

Last updated Apr 1, 2026

Compare and contrast key facts about Atmos Energy Corporation (ATO) and State Street SPDR S&P 500 ETF (SPY).

SPY is a passively managed fund by State Street that tracks the performance of the S&P 500 Index. It was launched on Jan 22, 1993.

Performance

ATO vs. SPY - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Atmos Energy Corporation (ATO) and State Street SPDR S&P 500 ETF (SPY). The values are adjusted to include any dividend payments, if applicable.

ATO vs. SPY - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ATO Atmos Energy Corporation	10.81%	23.07%	23.35%	6.17%	9.63%	12.75%	-12.73%	23.14%	10.39%	18.41%
SPY State Street SPDR S&P 500 ETF	-4.37%	17.72%	24.89%	26.18%	-18.18%	28.73%	18.33%	31.22%	-4.57%	21.71%

Returns By Period

In the year-to-date period, ATO achieves a 10.81% return, which is significantly higher than SPY's -4.37% return. Over the past 10 years, ATO has underperformed SPY with an annualized return of 12.12%, while SPY has yielded a comparatively higher 13.98% annualized return.

ATO

• 1D: -0.16%
• 1M: -1.11%
• YTD: 10.81%
• 6M: 9.41%
• 1Y: 22.16%
• 3Y*: 20.97%
• 5Y*: 16.33%
• 10Y*: 12.12%

SPY

• 1D: 2.91%
• 1M: -4.94%
• YTD: -4.37%
• 6M: -1.82%
• 1Y: 17.59%
• 3Y*: 18.19%
• 5Y*: 11.69%
• 10Y*: 13.98%

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

Return for Risk

ATO vs. SPY — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

ATO

ATO Risk / Return Rank: 81
ATO Sharpe Ratio Rank: 83
ATO Sortino Ratio Rank: 77
ATO Omega Ratio Rank: 77
ATO Calmar Ratio Rank: 88
ATO Martin Ratio Rank: 83

SPY

SPY Risk / Return Rank: 64
SPY Sharpe Ratio Rank: 56
SPY Sortino Ratio Rank: 60
SPY Omega Ratio Rank: 65
SPY Calmar Ratio Rank: 65
SPY Martin Ratio Rank: 75

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

ATO vs. SPY - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Atmos Energy Corporation (ATO) and State Street SPDR S&P 500 ETF (SPY). 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.

	ATO	SPY	Difference
Sharpe ratio Return per unit of total volatility	1.39	0.93	+0.47
Sortino ratio Return per unit of downside risk	1.88	1.45	+0.43
Omega ratio Gain probability vs. loss probability	1.26	1.22	+0.03
Calmar ratio Return relative to maximum drawdown	3.31	1.53	+1.79
Martin ratio Return relative to average drawdown	6.69	7.30	-0.61
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

ATO vs. SPY - Sharpe Ratio Comparison

The current ATO Sharpe Ratio is 1.39, which is higher than the SPY Sharpe Ratio of 0.93. The chart below compares the historical Sharpe Ratios of ATO and SPY, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	ATO	SPY	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.39	0.93	+0.47
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.89	0.69	+0.20
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.57	0.78	-0.21
Sharpe Ratio (All Time) Calculated using the full available price history	0.53	0.56	-0.03

Correlation

The correlation between ATO and SPY is 0.36, which is considered to be low. This implies their price changes are not closely related. A low correlation is generally favorable for portfolio diversification, as it helps to reduce overall risk by spreading it across multiple assets with different performance patterns.

Dividends

ATO vs. SPY - Dividend Comparison

ATO's dividend yield for the trailing twelve months is around 2.02%, more than SPY's 1.14% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
ATO Atmos Energy Corporation	2.02%	2.15%	2.36%	2.61%	2.48%	2.44%	2.46%	1.92%	2.14%	2.14%	2.31%	2.52%
SPY State Street SPDR S&P 500 ETF	1.14%	1.07%	1.21%	1.40%	1.65%	1.20%	1.52%	1.75%	2.04%	1.80%	2.03%	2.06%

Drawdowns

ATO vs. SPY - Drawdown Comparison

The maximum ATO drawdown since its inception was -51.94%, smaller than the maximum SPY drawdown of -55.19%. Use the drawdown chart below to compare losses from any high point for ATO and SPY.

Drawdown Indicators

	ATO	SPY	Difference
Max Drawdown Largest peak-to-trough decline	-51.94%	-55.19%	+3.25%
Max Drawdown (1Y) Largest decline over 1 year	-7.20%	-12.05%	+4.85%
Max Drawdown (5Y) Largest decline over 5 years	-19.08%	-24.50%	+5.42%
Max Drawdown (10Y) Largest decline over 10 years	-32.91%	-33.72%	+0.81%
Current Drawdown Current decline from peak	-2.05%	-6.24%	+4.19%
Average Drawdown Average peak-to-trough decline	-8.58%	-9.09%	+0.51%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.57%	2.52%	+1.05%

Volatility

ATO vs. SPY - Volatility Comparison

The current volatility for Atmos Energy Corporation (ATO) is 3.83%, while State Street SPDR S&P 500 ETF (SPY) has a volatility of 5.31%. This indicates that ATO experiences smaller price fluctuations and is considered to be less risky than SPY based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ATO	SPY	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.83%	5.31%	-1.48%
Volatility (6M) Calculated over the trailing 6-month period	10.28%	9.47%	+0.81%
Volatility (1Y) Calculated over the trailing 1-year period	16.01%	19.05%	-3.04%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.47%	17.06%	+1.41%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.21%	17.92%	+3.29%