ATO vs. ^GSPC

Last updated Apr 2, 2026

Compare and contrast key facts about Atmos Energy Corporation (ATO) and S&P 500 Index (^GSPC).

Performance

ATO vs. ^GSPC - Performance Comparison

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

ATO vs. ^GSPC - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
ATO Atmos Energy Corporation	11.27%	23.07%	23.35%	6.17%	9.63%	12.75%	-12.73%	23.14%	10.39%	18.41%
^GSPC S&P 500 Index	-3.95%	16.39%	23.31%	24.23%	-19.44%	26.89%	16.26%	28.88%	-6.24%	19.42%

Returns By Period

In the year-to-date period, ATO achieves a 11.27% return, which is significantly higher than ^GSPC's -3.95% return. Both investments have delivered pretty close results over the past 10 years, with ATO having a 12.17% annualized return and ^GSPC not far ahead at 12.24%.

ATO

• 1D: 0.42%
• 1M: -0.84%
• YTD: 11.27%
• 6M: 10.75%
• 1Y: 22.38%
• 3Y*: 21.13%
• 5Y*: 16.42%
• 10Y*: 12.17%

^GSPC

• 1D: 0.72%
• 1M: -4.45%
• YTD: -3.95%
• 6M: -2.02%
• 1Y: 16.73%
• 3Y*: 16.96%
• 5Y*: 10.34%
• 10Y*: 12.24%

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

Return for Risk

ATO vs. ^GSPC — Risk / Return Rank

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

ATO

ATO Risk / Return Rank: 80
ATO Sharpe Ratio Rank: 82
ATO Sortino Ratio Rank: 75
ATO Omega Ratio Rank: 76
ATO Calmar Ratio Rank: 86
ATO Martin Ratio Rank: 81

^GSPC

^GSPC Risk / Return Rank: 67
^GSPC Sharpe Ratio Rank: 63
^GSPC Sortino Ratio Rank: 64
^GSPC Omega Ratio Rank: 69
^GSPC Calmar Ratio Rank: 60
^GSPC Martin Ratio Rank: 77

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. ^GSPC - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Atmos Energy Corporation (ATO) and S&P 500 Index (^GSPC). 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	^GSPC	Difference
Sharpe ratio Return per unit of total volatility	1.41	0.92	+0.49
Sortino ratio Return per unit of downside risk	1.90	1.41	+0.48
Omega ratio Gain probability vs. loss probability	1.26	1.21	+0.04
Calmar ratio Return relative to maximum drawdown	3.15	1.41	+1.73
Martin ratio Return relative to average drawdown	6.35	6.61	-0.26
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. ^GSPC - Sharpe Ratio Comparison

The current ATO Sharpe Ratio is 1.41, which is higher than the ^GSPC Sharpe Ratio of 0.92. The chart below compares the historical Sharpe Ratios of ATO and ^GSPC, 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	^GSPC	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.41	0.92	+0.49
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.89	0.61	+0.28
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.58	0.68	-0.10
Sharpe Ratio (All Time) Calculated using the full available price history	0.53	0.46	+0.08

Correlation

The correlation between ATO and ^GSPC is 0.33, 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.

Drawdowns

ATO vs. ^GSPC - Drawdown Comparison

The maximum ATO drawdown since its inception was -51.94%, smaller than the maximum ^GSPC drawdown of -56.78%. Use the drawdown chart below to compare losses from any high point for ATO and ^GSPC.

Drawdown Indicators

	ATO	^GSPC	Difference
Max Drawdown Largest peak-to-trough decline	-51.94%	-56.78%	+4.84%
Max Drawdown (1Y) Largest decline over 1 year	-7.20%	-12.14%	+4.94%
Max Drawdown (5Y) Largest decline over 5 years	-19.08%	-25.43%	+6.35%
Max Drawdown (10Y) Largest decline over 10 years	-32.91%	-33.92%	+1.01%
Current Drawdown Current decline from peak	-1.64%	-5.78%	+4.14%
Average Drawdown Average peak-to-trough decline	-8.58%	-10.75%	+2.17%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.57%	2.60%	+0.97%

Volatility

ATO vs. ^GSPC - Volatility Comparison

The current volatility for Atmos Energy Corporation (ATO) is 3.82%, while S&P 500 Index (^GSPC) has a volatility of 5.37%. This indicates that ATO experiences smaller price fluctuations and is considered to be less risky than ^GSPC based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ATO	^GSPC	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.82%	5.37%	-1.55%
Volatility (6M) Calculated over the trailing 6-month period	10.27%	9.55%	+0.72%
Volatility (1Y) Calculated over the trailing 1-year period	15.96%	18.33%	-2.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.46%	16.90%	+1.56%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.21%	18.05%	+3.16%