ONE Gas : March Investor Update

ONE Gas, Inc.

15 E 5th Street Tulsa, OK 74103 www.onegas.com

Erin Dailey

Director, Investor Relations and Sustainability

1. 947-7411erin.dailey@onegas.com

Statements contained in this presentation that include or refer to Company expectations, our business outlook, our future plans or predictions relating to any matters should be considered forward-looking statements that are covered by the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, the Securities Act of 1933 and the Securities and Exchange Act of 1934, each as amended. All statements, other than statements of historical facts, included in this presentation are forward-looking statements. Words such as "anticipates," "expects," "projects," "intends," "goals," "plans," "potential," "might," "believes," "target," "objective," "strategy," "opportunity," "pursue," "budgets," "outlook," "trends," "focus," "on schedule," "on track," "poised," "slated," "seeks," "estimates," "forecasts," "guidance," "scheduled," "continues," "may," "will," "would," "should," "could," "likely," and variations of such words and similar expressions are intended to identify such forward-looking statements. One should not place undue reliance on forward-looking statements. In addition, statements that refer to or are based on estimates, forecasts, projections, uncertain events or assumptions, including statements relating to market opportunities, future products or processes and the expected availability and benefits of such products or processes, and anticipated trends in our businesses or the markets relevant to them, including those developments relating to regulation and litigation trends and developments, also identify forward-looking statements. Such statements are based on management's expectations as of the date of this investor presentation, unless an earlier date is indicated, and involve many risks and uncertainties, known and unknown, that could cause actual results, performance or achievements to differ materially from those expressed or implied in these forward-looking statements.

It is important to note that the actual results could differ materially from those projected in such forward-looking statements. Important risks and uncertainties that could cause actual results to differ materially from the company's expectations include, but are not limited to, our ability to recover, manage and maintain costs; the concentration of our operations in Oklahoma, Kansas and Texas; regulatory or legislative changes in the jurisdictions in which we operate; the length and severity of unpredictable events, including, but not limited to, pandemics, threatened terrorism, war or cyber-attacks or breaches, or extreme weather events, including those related to climate change; the competitive implications of alternative sources of energy and efforts to conserve energy; our competitive position, including, but not limited to our ability to secure competitive sourcing and pricing and our ability to compete with respect to expansion and infrastructure; the economic climate and our comparable economic position; our access to capital and the restrictions that result from our current capital arrangements; the effectiveness of our risk mitigation and compliance efforts; the uncertainties of any estimates or assumptions we use in our projections; our strategic and transactional efforts and future plans; and costs and uncertainties relating to our workforce, and other risks and uncertainties, including those that are set forth in ONE Gas' earnings release dated Feb. 21, 2024, which is included as an exhibit to ONE Gas' Form 8-K furnished to the SEC on such date.

For additional information regarding these and other factors that could cause actual results to differ materially from such forward-looking statements, refer to ONE Gas' Securities and Exchange Commission filings., including the Company's most recent reports on Forms 10-K and 10-Q. Copies of the Company's Form 10-K,10-Q and 8-K reports may be obtained by visiting our "Investors" website under "Financials & Filings" at https://www.onegas.com/investors/financials-and-filings/quarterly-results/default.aspx or the SEC's website at www.sec.gov. Other unpredictable or unknown factors not discussed in this presentation could also have material adverse effects on the Company, its operations or the outcomes described in the forward-looking statements in this presentation or in the Company's filings with the Securities and Exchange Commission.

All future cash dividends discussed in this presentation are subject to the approval of the ONE Gas board of directors.

All references in this presentation to guidance are based on news releases or disclosures issued on or before Feb. 21, 2024, and are not being updated or affirmed by this presentation. ONE Gas does not undertake, and expressly disclaims any duty, to update any statement made in this presentation, whether as a result of new information, new developments or otherwise, except to the extent that disclosure may be required by law.

About Us

ONE Gas, Inc. (NYSE: OGS) is a 100-percentregulated natural gas utility and is one of the largest natural gas utilities in the United States.

ONE Gas provides natural gas distribution services to approximately 2.3 million customers in Kansas, Oklahoma and Texas.

Its largest natural gas distribution markets by customer count are

Oklahoma City and Tulsa, Oklahoma; Kansas City, Wichita and

Topeka, Kansas; and Austin and El Paso, Texas.

We deliver natural gas for a better tomorrow.

71% market share, the largest in Kansas

89% market share, the largest in Oklahoma

13% market share, the third largest in Texas

2024 EPS guidance

of $3.70-$4.00

• 2024-28EPS growth of 4-6%

Launched

renewable natural

gas program in Oklahoma

We estimate

$750 million in

2024 capital investments

Increased storage to ~58 Bcf, +20% from pre-Winter Storm Uri levels

Replaced over 500

miles of

transmission,

main and service

lines in 2023

6th consecutive

AGA safety award for lowest rate of serious injury

Added ~23,000 new customer connections

Pay metric tied to

emissions

reduction goal,

driven by pipeline

replacement

Safety

We are committed to operating safely and in an environmentally responsible manner.

Ethics

We are accountable to

the highest ethical standards and are committed to compliance.

Inclusion &

Diversity

We embrace an inclusive and diverse culture that encourages collaboration. Every employee makes a difference and contributes to our success.

Service

We provide

exceptional service to our customers and support each other.

Value

We create value for

all stakeholders; our customers, employees, investors and communities.

Favorable Regional Growth Dynamics

Growing Demand for Natural Gas Provides Long-Term Growth Opportunity

Durable residential and commercial development, anchored to economic growth, is driving system expansion

Strong support for natural gas with energy choice legislation in all jurisdictions

Projecting five-year compound annual customer growth of 0.9%

• Texas - 1.2%
• Oklahoma - 1.0%
• Kansas - 0.4%

Moderated near-term customer growth is reflective of higher interest rates; upside potential as builder activity reignites

Source: Bureau of Labor & Statistics EMSI/QCEW Data

I-35 corridor

I-35 corridor fastest growing population in the U.S

ONE Gas positioned in KS, OK and TX with 5 of the main metro areas in the corridor

Largest warehouse labor force in the country - expected to grow 20% over next decade due to location along primary USMCA transport route

El Paso is also growing significantly but not considered in the I-35 corridor