Exhibit 99.5

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

The following sets forth certain unaudited pro forma condensed combined financial data giving effect to the Polygon Acquisition, this offering of $250.0 million in notes, the concurrent offering of $50.0 million in additional 2019 notes, $120.0 million in expected borrowings under the Senior Unsecured Facility and the use of $119.7 million in cash on hand (including $100.0 million of cash generated from the Land Bank Arrangements) to finance the Polygon Acquisition and to pay related fees and expenses. The unaudited pro forma condensed combined financial data set forth below has been presented for informational purposes only. The pro forma data is not necessarily indicative of what the combined Company’s financial position or results of operations actually would have been had the Polygon Acquisition been completed as of the dates indicated. In addition, the unaudited pro forma condensed combined financial data does not purport to project the future financial position or operating results of the Company following the consummation of the Polygon Acquisition. There were no material transactions between the Company and Polygon Northwest Homes during the periods presented in the unaudited pro forma condensed combined financial statements that would need to be eliminated.

The unaudited pro forma condensed combined balance sheet assumes that the Polygon Acquisition took place on March 31, 2014.

The unaudited pro forma condensed combined statement of operations for the three months ended March 31, 2014 assumes that the Polygon Acquisition took place on January 1, 2013.

The unaudited pro forma condensed combined statement of operations for the three months ended March 31, 2013 assumes that the Polygon Acquisition took place on January 1, 2013.

The unaudited pro forma condensed combined statement of operations for the year ended December 31, 2013 assumes that the Polygon Acquisition took place on January 1, 2013.

The historical consolidated financial information has been adjusted in the unaudited pro forma condensed combined financial statements to give effect to pro forma events that are (1) directly attributable to the Polygon Acquisition, (2) factually supportable, and (3) with respect to the statements of operations, expected to have a continuing impact on the combined company. The unaudited pro forma condensed combined financial information should be read in conjunction with the accompanying notes to the unaudited pro forma condensed combined financial statements. In addition, the unaudited pro forma condensed combined financial information was based on and should be read in conjunction with the following historical consolidated financial statements and accompanying notes of the Company for the applicable periods, which are incorporated by reference in this offering memorandum, and Polygon Northwest Homes for the applicable periods, which are included in this offering memorandum:

The unaudited pro forma condensed combined financial data has been prepared using the acquisition method of accounting under GAAP, which is subject to change and interpretation. The Company has been treated

1

as the acquiror in the Polygon Acquisition for accounting purposes. The acquisition method of accounting is dependent upon certain valuations and other studies that have yet to commence or progress to a stage where there is sufficient information for a definitive measurement. Accordingly, the pro forma adjustments are preliminary and have been made solely for the purpose of providing unaudited pro forma condensed combined financial data. Differences between these preliminary estimates and the final acquisition accounting will occur and these differences could have a material impact on the accompanying unaudited pro forma condensed combined financial statements and the combined company’s future results of operations and financial position.

The unaudited pro forma condensed combined financial data does not reflect any cost savings, operating synergies or revenue enhancements that the combined company may achieve as a result of the Polygon Acquisition, the costs to combine the operations of the Company and Polygon Northwest Homes or the costs necessary to achieve any of the foregoing cost savings, operating synergies and revenue enhancements.

2

Unaudited Pro Forma Condensed Combined Balance Sheet

As of March 31, 2014

(in thousands, except per share data)

See accompanying notes to the unaudited pro forma condensed combined financial statements, which are an integral part of these statements

3

Unaudited Pro Forma Condensed Combined Statement of Operations

For the Three Months Ended March 31, 2014

(in thousands, except per share data)

See accompanying notes to the unaudited pro forma condensed combined financial statements, which are an integral part of these statements

4

Unaudited Pro Forma Condensed Combined Statement of Operations

For the Three Months Ended March 31, 2013

(in thousands, except per share data)

See accompanying notes to the unaudited pro forma condensed combined financial statements, which are an integral part of these statements

5

Unaudited Pro Forma Condensed Combined Statement of Operations

For the Year Ended December 31, 2013

(in thousands, except per share data)

See accompanying notes to the unaudited pro forma condensed combined financial statements, which are an integral part of these statements

6

Notes to the Unaudited Pro Forma Condensed Combined Financial Statements

On June 22, 2014, the Company entered into a definitive purchase and sale agreement (the “Acquisition Agreement”) with PNW Home Builders, L.L.C. (“PNW Parent”), PNW Home Builders North, L.L.C., PNW Home Builders South, L.L.C. and Crescent Ventures, L.L.C. (collectively, the “Sellers”), to acquire the residential homebuilding business of PNW Parent. The residential homebuilding operations of Polygon Northwest Homes and its affiliates are not conducted through a stand-alone legal entity, but rather are a combination of the residential homebuilding operations owned by Sellers through their direct and indirect ownership of certain limited liability companies that own real property (such operations being referred to herein as “Polygon Northwest Homes”) and conduct business as Polygon Northwest Company (“Polygon”). Pursuant to the Acquisition Agreement, California Lyon has agreed to purchase Polygon Northwest Homes through its acquisition of the membership interests of the underlying limited liability companies and certain service companies and other assets, for an aggregate cash purchase price of $520.0 million (the “Polygon Acquisition”). Separately, PNW Parent is also engaged in commercial building activities and rental operations, which are excluded from the Polygon Acquisition and are not being acquired by us.

The $520.0 million purchase price provided for in the Acquisition Agreement will take place on a “zero cash, zero debt” basis, such that the Company will not be acquiring any cash on the balance sheet of Polygon Northwest Homes at closing and will not be assuming any of Polygon Northwest Homes’ existing debt, which will get paid off by the Sellers in connection with closing of the Polygon Acquisition. Sellers will retain all pre-closing liabilities pursuant to the terms of the Acquisition Agreement, except for certain limited assumed current liabilities including accounts payable and accrued other expenses. The purchase price is subject to working capital adjustments and pursuant to the terms of the Acquisition Agreement, we expect the Polygon Acquisition to close on or before August 15, 2014.

The unaudited pro forma condensed combined financial statements were prepared using the acquisition method of accounting, and were based on the historical financial statements of the Company and Polygon Northwest Homes. The historical William Lyon Homes and Polygon Northwest Homes columns in the Unaudited Pro Forma Condensed Combined Balance Sheet and the Condensed Combined Statement of Operations represent the unaudited results as of March 31, 2014 and for the three months ended March 31, 2014 and 2013, and for the year ended December 31, 2013.

The Unaudited Pro Forma Condensed Combined Statement of Operations give effect to the Pro Forma adjustments (as described below) as if the Polygon Acquisition had occurred or had become effective as of January 1, 2013. The Unaudited Condensed Combined Balance Sheet gives effect to the Pro Forma adjustments as if the Polygon Acquisition had occurred on March 31, 2014.

The unaudited pro forma condensed combined financial information is based on available information and certain assumptions that the Company believes are reasonable. The unaudited pro forma condensed combined financial information is for illustrative and informational purposes only and does not necessarily reflect the Company’s results of operations or financial condition had the pro forma transactions occurred at an earlier date and should not be considered representative of the Company’s future financial condition or results of operations.

Accounting standards require that the assets and liabilities of the acquired entity are recognized at their acquisition-date fair value and that the consideration transferred be measured at the closing date of the acquisition at the then-current market price.

GAAP defines the term “fair value”, and sets forth the valuation requirements for any asset or liability measured at fair value, and specifies a hierarchy of valuation techniques based on the inputs used to develop the fair value measures. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Under this definition, market participants are assumed to be buyers and sellers in the principal (or most advantageous) market for the

7

asset or liability. Many of these fair value measurements can be highly subjective, and it is also possible that other professionals, applying reasonable judgment to the same facts and circumstances, could develop and support a range of alternative estimated amounts.

Under the acquisition method of accounting, the assets acquired and liabilities assumed are recorded as of the completion of the acquisition, primarily at their respective fair values and added to the existing assets and liabilities of the Company. Financial statements and reported results of operations of the Company issued after the completion of the acquisition will reflect these values, but will not be retroactively restated to reflect the historical financial position or results of operations of Polygon Northwest Homes as of any date or for any period prior to the acquisition.

The Company will continue to review Polygon Northwest Homes’ accounting policies. As a result of the ongoing review, the Company may identify differences between the accounting policies of the two companies that could have a material impact on the combined pro forma financial statements. At this time, the Company is not aware of any differences that would have a material impact on the combined pro forma financial statements. The unaudited pro forma condensed combined financial statements assume there are no differences in accounting policies between the two companies.

The pro forma adjustments are preliminary and based on estimates of the fair value and useful lives of the assets acquired and liabilities assumed as of the transaction date, and have been prepared to illustrate the estimated effect of the transaction. Due to the preliminary nature of these estimates, actual results could differ significantly from such estimates.

(a) Inventory

Acquisition date fair value of inventory was estimated using a combination of the discounted cash flow method as well as a residual value and spot value underwriting approach on land and land under development that the Company traditionally applies during the land acquisition process. The final determination of the fair value of real estate inventory could be impacted by expected average selling price, sales pace, cost to complete estimates, highest and best use of the projects prior to acquisition, or comparable land values.

(b) Intangible Assets

The Company valued the estimated homes in backlog as an Intangible Asset using the income method, assuming a with/without approach to income. The final determination of the fair value of backlog will depend on the final number of homes in backlog received as of the transaction date, as well as the expected selling price of those homes.

The acquisition date fair value of brand intangible was estimated using comparable values ascribed in other recent market transactions, and taking into account Polygon Northwest Homes market position as a leading builder in the Seattle and Portland residential markets. This asset is deemed to have an indefinite life.

(c) Other Assets

The Company will acquire a 50% interest in a joint venture mortgage business. The acquisition date fair value assigned to this joint venture was estimated using the discounted cash flow method. The final determination of the fair value of this joint venture will depend on the estimated cash flow streams and income of the joint venture.

The final determination of purchase price allocation upon the consummation of the Polygon Acquisition will be based on Polygon Northwest Homes’ net assets acquired as of that date, and will depend on a number of factors which cannot be predicted with certainty at this time. The purchase price allocation may change

8

materially based on the receipt of more detailed information, and as such the actual allocations may differ from the pro forma adjustments presented. There can be no assurances that these additional analyses and final valuations will not result in significant changes to the estimates of fair value set forth below.

The following table sets forth (in thousands) a preliminary allocation of the estimated purchase price consideration to the identifiable tangible and intangible assets acquired and liabilities assumed of Polygon Northwest Homes, with the excess recorded as goodwill:

9

The Company anticipates that the Polygon Acquisition will be funded through a combination of borrowings and the transfer of land to an unrelated party, as part of a financing transaction. The Company will subsequently enter into an option agreement to repurchase the land in a series of scheduled take-downs as finished lots in the future. Estimated sources and uses of cash (in thousands) related to the Polygon Acquisition are as follows:

As a result of the borrowings assumed above, the Company will incur approximately $27.2 million of incremental interest based upon the assumed interest rates in effect at issuance and assuming debt is outstanding for an entire year. A 0.125% increase or decrease in the interest rates assumed above would increase or decrease interest incurred expense on a pro forma basis by $0.5 million.

In addition to the incremental interest assumed above is the amortization of $14.8 million of deferred financing fees incurred as part of the financing transaction. As the Company anticipates that qualifying real estate projects under development will exceed total debt, the additional interest incurred will initially be capitalized to inventory in accordance with ASC topic 835 “Capitalization of Interest”.

10

Cost of sales - homes has been adjusted to reflect the impact of the purchase price allocation of Polygon Northwest Homes’ inventory. During the first year subsequent to the Polygon Acquisition, the Company expects Cost of revenues - homes on the acquired inventory of Polygon Northwest Homes to be approximately 85.0% of Homebuilding revenue for three months ended March 31, 2013, and full year ended December 31, 2013, and approximately 84.0% of Homebuilding revenue for the three months ended March 31, 2014.

As a result of the borrowings entered into in order to fund the Polygon Acquisition, the Company will incur approximately $27.2 million of incremental interest on an annual basis, based upon the assumed interest rates in effect at issuance and assuming debt is outstanding for an entire year. As the Company anticipates that qualifying real estate projects under development will exceed total debt, the additional interest incurred will initially be capitalized to inventory in accordance with ASC topic 835 “Capitalization of Interest”. The Company estimates that the amount of interest expensed through Cost of sales will approximate 4.0% of homebuilding revenues under the current interest capitalization model, which is included in the pro forma costs of sales rate mentioned above.

As such, for the three months ended March 31, 2014, three months ended March 31, 2013, and the year ended December 31, 2013, approximately $6.4 million, $3.8 million and $33.7 million, respectively, are included as an increase to Cost of sales - homes in the unaudited pro forma condensed consolidated statement of operations.

As Polygon Northwest Homes was not previously required to record a provision for income tax due to its organizational structure, the Company applied statutory tax rates to the pro forma adjusted income before taxes to compute pro forma Provision for income taxes that would have been recorded had Polygon Northwest been a part of the Company’s consolidated operations during the three months ended March 31, 2014 and 2013, and year ended December 31, 2013. The pro forma adjustments are calculated below:

11