Exhibit 99.3

Introduction to the Unaudited Pro Forma Condensed Financial Statements

On April 17, 2017, our consolidated master limited partnership, Williams Partners L.P., announced that it agreed to sell Williams Olefins, L.L.C., a wholly owned subsidiary which owns an 88.46 percent undivided ownership interest in a Geismar, Louisiana, olefins plant and associated complex for $2.1 billion in cash. On July 6, 2017, the sale was completed and we received cash proceeds totaling $2.084 billion, reflecting adjustments for the estimated net working capital at closing and subject to final determination.

The following unaudited pro forma financial statements have been developed by applying pro forma adjustments to the individual historical audited and unaudited financial statements of The Williams Companies, Inc. to reflect the disposition. The following unaudited pro forma condensed balance sheet as of March 31, 2017, has been prepared to give effect to the transaction as if the divestiture had occurred on March 31, 2017. The following unaudited pro forma condensed statements of income for the three months ended March 31, 2017, and year ended December 31, 2016, have been prepared to give effect to the transaction as if the divestiture had occurred at the beginning of 2016. Our historical condensed consolidated financial statements have been derived from and should be read together with the historical audited consolidated financial statements and related notes in Exhibit 99.1 of our Form 8-K dated May 25, 2017, and the historical unaudited consolidated financial statements and related notes in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2017.

The unaudited pro forma condensed financial statements are presented for illustrative purposes only to reflect the sale of Williams Olefins, L.L.C. and do not represent what our results of operations or financial position would actually have been had the sale occurred on the dates noted above, or project our results of operations or financial position for any future periods. The pro forma adjustments are based on available information and certain assumptions that management believes are factually supportable and are expected to have a continuing impact on our results of operations. All pro forma adjustments and their underlying assumptions are described more fully in the notes to the unaudited pro forma condensed financial information.

The Williams Companies, Inc.

Unaudited Pro Forma Condensed Balance Sheet

As of March 31, 2017

($ in millions)

	Historical
	The Williams Companies, Inc.			Pro Forma Adjustments			Pro Forma
ASSETS
Current assets:
Cash and cash equivalents	$	639		$	2,084		$	2,723
Trade accounts and other receivables – net		867			—			867
Inventories		148			—			148
Assets held for sale		1,023			(999	)		24
Other current assets and deferred charges		168			—			168
Total current assets		2,845			1,085			3,930
Investments		6,738			—			6,738
Property, plant, and equipment, at cost		38,342			—			38,342
Accumulated depreciation and amortization		(10,580	)		—			(10,580	)
Property, plant, and equipment – net		27,762			—			27,762
Intangible assets – net of accumulated amortization		9,570			—			9,570
Regulatory assets, deferred charges, and other		597			—			597
Total assets	$	47,512		$	1,085		$	48,597
LIABILITIES AND EQUITY
Current liabilities:
Accounts payable	$	680		$	—		$	680
Liabilities held for sale		43			(43	)		—
Accrued liabilities		1,322			45			1,367
Total current liabilities		2,045			2			2,047
Long-term debt		21,825			—			21,825
Deferred income tax liabilities		5,133			301			5,434
Regulatory liabilities, deferred income, and other		3,100			—			3,100
Contingent liabilities
Equity:
Stockholders’ equity		8,444			500			8,944
Noncontrolling interests in consolidated subsidiaries		6,965			282			7,247
Total equity		15,409			782			16,191
Total liabilities and equity	$	47,512		$	1,085		$	48,597

See accompanying notes.

The Williams Companies, Inc.

Unaudited Pro Forma Condensed Statement of Income

For the three months ended March 31, 2017

($ in millions, except per-share amounts)

	Historical
	The Williams Companies, Inc.			Pro Forma Adjustments			Pro Forma
Revenues:
Service revenues	$	1,261		$	(4	)	$	1,257
Product sales		727			(115	)		612
Total revenues		1,988			(119	)		1,869
Costs and expenses:
Product costs		579			(55	)		524
Operating and maintenance expenses		368			(22	)		346
Depreciation and amortization expenses		442			(13	)		429
Selling, general, and administrative expenses		161			(5	)		156
Other (income) expense – net		5			—			5
Total costs and expenses		1,555			(95	)		1,460
Operating income (loss)		433			(24	)		409
Equity earnings (losses)		107			—			107
Other investing income-net		272			—			272
Interest expense		(280	)		1			(279	)
Other income (expense) – net		74			—			74
Income (loss) before income taxes		606			(23	)		583
Provision (benefit) for income taxes		37			(6	)		31
Net income (loss)		569			(17	)		552
Less: Net income (loss) attributable to noncontrolling interests		196			(6	)		190
Net income (loss) attributable to The Williams Companies, Inc.	$	373		$	(11	)	$	362
Amount attributable to The Williams Companies, Inc.
Basic earnings (loss) per common share:
Net income (loss)	$	.45					$	.44
Weighted-average shares (thousands)		824,548						824,548
Diluted earnings (loss) per common share:
Net income (loss)	$	.45					$	.44
Weighted-average shares (thousands)		826,476						826,476

See accompanying notes.

The Williams Companies, Inc.

Unaudited Pro Forma Condensed Statement of Income

For the year ended December 31, 2016

($ in millions, except per-share amounts)

	Historical
	The Williams Companies, Inc.			Pro forma Adjustments			Pro Forma
Revenues
Service revenues	$	5,171		$	(13	)	$	5,158
Product sales		2,328			(427	)		1,901
Total revenues		7,499			(440	)		7,059
Costs and expenses:
Product costs		1,725			(150	)		1,575
Operating and maintenance expenses		1,580			(86	)		1,494
Depreciation and amortization expenses		1,763			(52	)		1,711
Selling, general, and administrative expenses		723			(19	)		704
Impairment of certain assets		873			—			873
Other (income) expense – net		135			—			135
Total costs and expenses		6,799			(307	)		6,492
Operating income (loss)		700			(133	)		567
Equity earnings (losses)		397			—			397
Impairment of equity-method investments		(430	)		—			(430	)
Other investing income (loss) – net		63			—			63
Interest expense		(1,179	)		—			(1,179	)
Other income (expense) – net		74			—			74
Income (loss) from continuing operations before income taxes		(375	)		(133	)		(508	)
Provision (benefit) for income taxes		(25	)		(30	)		(55	)
Net income (loss)		(350	)		(103	)		(453	)
Less: Net income (loss) attributable to noncontrolling interests		74			(53	)		21
Net income (loss) attributable to the Williams Companies, Inc.	$	(424	)	$	(50	)	$	(474	)
Amounts attributable to The Williams Companies, Inc.:
Basic earnings (loss) per common share:
Net income (loss)	$	(.57	)				$	(.63	)
Weighted-average shares (thousands)		750,673						750,673
Diluted earnings (loss) per common share:
Net income (loss)	$	(.57	)				$	(.63	)
Weighted-average shares (thousands)		750,673						750,673

See accompanying notes.

Note 1. Pro Forma Adjustments

Unaudited Pro Forma Condensed Balance Sheet Adjustments

The pro forma adjustments reflect $2.084 billion of cash received upon the sale of Williams Olefins, L.L.C., the removal of the related historical net assets of the disposal group, an accrual for certain estimated transaction-related items associated with the sale, and the impact resulting from the expected gain on disposal. The gain has been tax affected at an estimated effective rate of 37.6 percent.

Unaudited Pro Forma Condensed Statements of Income Adjustments

The pro forma adjustments reflect the removal of the historical results of the disposal group, further adjusted to reflect the income attributable to the noncontrolling interests in Williams Partners L.P. and the effect of income taxes at an estimated effective rate of 37.6 percent. The pro forma adjustments do not reflect the expected gain on disposal, currently estimated to be approximately $1.083 billion, before income taxes.