Fourth Quarter 2025 Earnings

Fourth-Quarter 2025 Review

February 18, 2026

Recent Highlights

4Q'25 Highlights

Operational & Financial

Delaware Basin

Crude-oil and NGLs

Throughput

261 MBbls/d

7% Q-o-Q

DJ Basin

Natural gas

Throughput

1.53 Bcf/d

2% Q-o-Q

Total

Produced-Water Throughput

2,744 MBbls/d

121% Q-o-Q

Record 4Q'25

Adjusted EBITDA

$636 MM

Accomplishments

Generated our third consecutive quarter of record Adjusted EBITDA Achieved record crude-oil and NGLs throughput in the Delaware Basin and natural-gas throughput in the DJ Basin

Reduced 4Q'25 operation and maintenance expense by 12% compared to 4Q'241 Closed the acquisition of Aris Water Solutions, Inc. Commenced construction on North Loving II, with a planned start-up in early 2Q'27



Executed an agreement for incremental disposal capacity to support the Pathfinder pipeline, as previously announced

4

1) Excludes the Aris Water Solutions, Inc. ("Aris") acquisition.

2025 Highlights

Operational & Financial

Total

Natural-Gas

Throughput

5.2 Bcf/d

4% Y-o-Y1

Total

Crude-oil and NGLs

Throughput

514 MBbls/d

1% Y-o-Y2

Total

Produced-Water Throughput

1,578 MBbls/d

40% Y-o-Y

Full-Year

Adjusted EBITDA

$2.48 B

6% Y-o-Y

Accomplishments

Generated record Adjusted EBITDA and Free Cash Flow Achieved another year of record throughput across all three products in the Delaware Basin

Decreased O&M by more than $100 million from 1Q'25 to the 4Q'25, based on annualized run-rates Acquired Aris and sanctioned the Pathfinder pipeline, becoming a fully-integrated produced-water services provider

Constructed North Loving I and sanctioned North Loving II in the Delaware Basin, increasing basin processing capacity to ~2.6 Bcf/d3 when complete in early second quarter 2027 Increased distribution 4% and returned ~$1.43 billion of capital to unitholders

1. For the year-ended December 31, 2024, excludes an average of 38 MMcf/d of throughput associated with the sale of the Marcellus Interest gathering system in April 2024.

2. For the year-ended December 31, 2024, excludes an average of 23 MBbls/d of throughput associated with the sale of (i) Saddlehorn Pipeline LLC, Whitethorn Pipeline Company LLC, Panola Pipeline Company LLC, and Enterprise EF78 LLC in the first quarter of 2024, and (ii)

   Wamsutter Pipeline LLC in the third quarter of 2024. 5

3. Includes 215 MMcf/d of bypass capacity at the West Texas Complex and 100 MMcf/d of dedicated capacity at the Mi Vida plant.

Focused on Efficiency Improvement and Cost Reduction

Achieved cost reductions while focusing on growth

• Reduced operation and maintenance expense ("O&M")

  by 8% in 3Q'25 vs. 3Q'24, and 12% in 4Q'25 vs. 4Q'24

• Majority of O&M saving realized to date driven by field-level optimization and corporate process rationalization, which will continue in 2026, such as:

  • Asset maintenance programs and schedules

  • Rental fleets and contract workforce

  • Debottlenecking facilities and reducing offloads

  • Supply chain sourcing and contract renegotiation

• Improved facilities design expected to result in ~4% reduction2 to expansion capital in 2026

• Expect to realize incremental G&A savings and corporate capital spending reductions through IT and systems optimization in 2026

  $200

  $180

  $MM

  $160

  $140

  $120

  
  
  

  $100

  Quarterly O&M Total Operated Natural-gas Throughput
  
  

  6,500

  26% total operated natural-gas throughput growth since 1Q'23

  6,000

  5,500

  MMcf/d

  5,000

  4,500

  4,000

  3,500

  WES has eliminated more than $100 million1 in annualized O&M from 1Q'25 to 4Q'25, while

  continuing to implement its strategic growth strategy.

  1. Excludes utility costs and the Aris acquisition. 6

  2. Pertains to remaining expansion capital expenditure budget, excluding large expansion projects such as Pathfinder and North Loving II.

  Delaware Basin Natural-Gas Contract Renegotiation

  
  
  
  
  

  New agreements replace cost-of-service ("CoS") with fixed-fee rate structure

  Contract Terms and Benefits

Contract Strength Remains in Place

1) After the unit redemption, Occidental owns 150,374,176 WES common units and 9,060,641 WES GP units, resulting in total WES ownership of 39.5%.

$180

$160

$140

$120

$100

$80

$60

$40

$20

$0

Existing Contract Liability Incremental Contract Liability

Distribution Savings Cost Reduction Savings Through 4Q'25

Annual cash flow reduction offset by distribution savings, O&M cost reduction initiatives, and reduced capital expenditures.

Reduced Capex

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Fourth-Quarter Performance

Fourth-Quarter Operational Performance

3Q 2025 Actuals 4Q 2025 Actuals

Note: Represents total throughput attributable to WES, which excludes the 1.9% as of December 31, 2025 and 2.0% for all other periods presented limited partner interest in WES Operating owned by an Occidental subsidiary, and for natural-gas assets, the 25% third-party interest in 9

Chipeta, which collectively represent WES's noncontrolling interests.

Fourth-Quarter Financial Performance

($ in millions)

3Q 2025

Actuals

4Q 2025

Actuals

1. Includes net investing distributions from equity investments.

2. See slides 42 - 45 for a reconciliation of GAAP to non-GAAP measures and the corresponding definitions.

3. Cash distributions paid in third-quarter 2025, declared in second-quarter 2025.

4. Cash distributions paid in fourth-quarter 2025, declared in third-quarter 2025. Cash distributions declared in fourth-quarter 2025 were $379.7 million.

5. Represents limited partners' interest in net income (loss).

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Full-Year Performance

Full-Year Operational Performance

FY 2024 Actuals FY 2025 Actuals

Note: Represents total throughput attributable to WES, which excludes the 1.9% as of December 31, 2025 and 2.0% for all other periods presented Occidental subsidiary-owned limited partner interest in WES Operating, and for natural-gas assets, the 25% third-party interest in

Chipeta, which collectively represent WES's noncontrolling interests.

1. For the year-ended December 31, 2024, includes an average of 38 MMcf/d of throughput associated with the sale of the Marcellus Interest gathering system in April 2024.

2. For the year-ended December 31, 2024, includes an average of 23 MBbls/d of throughput associated with the sale of (i) Saddlehorn Pipeline LLC, Whitethorn Pipeline Company LLC, Panola Pipeline Company LLC, and Enterprise EF78 LLC in the first quarter of 2024, and (ii) 12

Wamsutter Pipeline LLC in the third quarter of 2024.

2025 Financial Scorecard

(millions, except where otherwise noted)

2025 Guidance 2025 Actuals

1. See slides 42 - 45 for a reconciliation of GAAP to non-GAAP measures and the corresponding definitions.

2. Accrual-based, includes equity investments, and excludes both capitalized interest and capital expenditures associated with the 25% third-party interest in Chipeta.

3. Represents cash distributions paid on a per-unit basis during 2025.

4. Represents cash distributions paid on an aggregate basis during 2025. 13

5. As of December 31, 2025. Total net debt outstanding divided by 2025 Adjusted EBITDA, which includes two and a half months of Aris.

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   Financial Outlook & Guidance

   
   
   
   
   

   WES's Strategic Organic Growth Plans

   
   
   

   Accretive organic projects support WES's multi-year growth outlook

   North Loving II

   • 300 MMcf/d cryogenic processing train at North Loving plant

   • Expected in-service in early

     2Q'27

   • Supported by producers' growth plans and West Texas Complex MVCs

   • North Loving I ramped up to 100% capacity within one month in February 2025

     
     
     

   • Increases WES's total Delaware Basin processing capacity to ~2.6 Bcf/d1

     Pathfinder Pipeline

     
     
     

   • ~800 MBbls/d of 30-inch poly-lined steel produced-water transportation pipeline

   • Supported by 280 MBbls/d of firm gathering and transportation and 220 MBbls/d of firm disposal capacities from Occidental2

   • Includes construction of additional produced-water infrastructure and SWDs

   • Executed agreement in 4Q'25 for incremental disposal capacity along pipeline and optimized route

   • Expected in-service in 1Q'27

   • ~65% of total project capex to be spent in 2026

   1. Includes 215 MMcf/d of bypass capacity at the West Texas complex and 100 MMcf/d of dedicated capacity at the Mi Vida plant. 15

   2. Includes new firm commitments for volumes that were previously forecasted.

WES's Capital Allocation Priorities

With net leverage1 at or near 3.0x - primary focus will be on expansion opportunities

Net Leverage Reduction1 and Adjusted EBITDA2 Growth

WES is committed to its capital-return framework and pursuing expansion opportunities that provide support for sustainable distribution growth.

16

Note: Per FactSet, S&P Capital IQ, and WES public filings.

1. As of December 31, 2025. Trailing twelve months. Total net debt outstanding divided by trailing twelve-month Adjusted EBITDA.

2. Trailing twelve months. See slides 42 - 45 for a reconciliation of GAAP to non-GAAP measures and the corresponding definitions.

2026 Financial & Operational Outlook

($ in millions)

Commodity

2026E Price

Assumption6 Price Change7

Estimated Impact to Adjusted EBITDA

Note: Based on current producer production-forecast information.

1. A reconciliation of the Adjusted EBITDA range to net cash provided by operating activities and net income (loss), and a reconciliation of the Distributable Cash Flow range to net income, is not provided because the items necessary to estimate such amounts are not reasonably estimable at this time. These items, net of tax, may include, but are not limited to, impairments of assets and other charges, divestiture costs, acquisition costs, or changes in accounting principles. All of these items could significantly impact such financial measures. At this time, WES is not able to estimate the aggregate impact, if any, of these items on future period reported earnings. Accordingly, WES is not able to provide a corresponding GAAP equivalent for the Adjusted EBITDA or Distributable Cash Flow ranges. For a definition of Adjusted EBITDA and Distributable Cash Flow, see slides 42 - 45.

2. Accrual-based, includes equity investments, and excludes both capitalized interest and capital expenditures associated with the 25% third-party interest in Chipeta.

3. Full-year 2026 distribution (paid in 2026) of at least $3.70 per unit, which includes the February 2026 distribution of $0.91 per unit. Subject to Board review and approval on a quarterly basis based on the needs of the business.

4. Estimated average yearly throughput in 2026 relative to average yearly throughput in 2025. Includes the impact of the Aris Water Solutions acquisition.

5. Assumes all other variables potentially impacting Adjusted EBITDA results, including but not limited to, throughput, gas-processing plant operating mode, producer recovery elections, and regional pricing differentials are held constant.

6. Full-year 2026 average pricing. 17

7. Natural-gas price change includes an equivalent percentage change in ethane prices. All other NGL price changes are included in price changes for crude oil, based on historical percentage of crude-oil prices.

2026 Adjusted EBITDA Guidance

EXPECTED ASSET-LEVEL EBITDA CONTRIBUTION1

62% Delaware Basin

53% Gas

15% Oil

32% Water

26% DJ Basin

89% Gas

11% Oil

4% Powder River

Basin

4% Equity Investments

4% Other2

1. Excludes G&A. Represents asset-level cash contribution to EBITDA. 18

2. South Texas, SW Wyoming, MIGC, and Utah assets.

2026 Capital Expenditures Guidance

1% Equity Investments

8% Powder River Basin

5% DJ Basin

74% Gas

26% Oil

& Other

5% Equity Investments

& Other

9% Well Connect

10% Maintenance & Regulatory1

86% Delaware Basin

37% Gas

4% Oil

59% Water

76% Expansion

Note: Accrual-based, includes equity investments, and excludes both capitalized interest and capital expenditures associated with the 25% third-party interest in Chipeta. 19

1. Maintenance & regulatory includes capital invested to ensure asset integrity and maintain proper operations, and projects required by regulatory agencies.

   
   
   

   Significant Return of Capital to Unitholders

   
   
   

   Targeting Mid-to-Low Single-Digits Annual Distribution Growth Rate

Targeting sustainable annual distribution growth

WES's Distribution History1

184% Distribution per Unit

Growth 2021 - 2025

WES has a consistent history of increasing the distribution, which should continue to be supported by growth in the underlying business and incremental Free Cash Flow3 generation.

Note: Excludes Enhanced Distribution paid in 2023.