SC 13D/A

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

RULE 13d-2(a)

(Amendment No. 8)

USG Corporation

(Name of Issuer)

Common Stock, Par Value $0.10 Per Share

(Title of Class of Securities)

90329405

(CUSIP Number)

Jorg Schanow, LL.M.

General Counsel

Gebr. Knauf KG

Am Bahnhof 7

97346 Iphofen

Federal Republic of Germany

(49) 9329-31-1091

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

March 23, 2018

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box o.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934, as amended  (“Securities Exchange Act”) or otherwise subject to the liabilities of that section of the Securities Exchange Act but shall be subject to all other provisions of the Securities Exchange Act.

(Continued on following pages)

CUSIP No.  90329405						13D
	1	Names of Reporting Persons I.R.S. Identification Nos. of Above persons [Entities Only] Gebr. Knauf KG
	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			o
	3	SEC Use Only
	4	Source of Funds WC
	5	Check Box if Disclosure of Legal Proceedings Is Required Pursuant to Item 2(d) or 2(e) o
	6	Citizenship or Place of Organization Federal Republic of Germany
Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 14,757,258
			8	Shared Voting Power -0-
			9	Sole Dispositive Power 14,757,258
			10	Shared Dispositive Power -0-
	11	Aggregate Amount Beneficially Owned by Each Reporting Person 14,757,258
	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares o
	13	Percent of Class Represented by Amount in Row (11) 10.46%*
	14	Type of Reporting Person PN

*  Based on 141,056,498 share of the Issuer’s common stock outstanding as of January 31, 2018 as reported in the Issuer’s Annual Report on Form 10-K for its fiscal year ended December 31, 2017.

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CUSIP No.  90329405						13D
	1	Names of Reporting Persons I.R.S. Identification Nos. of Above Persons [Entities Only] C & G Verwaltungs GmbH
	2	Check the Appropriate Box if a Member of a Group
		(a)			o
		(b)			o
	3	SEC Use Only
	4	Source of Funds AF
	5	Check Box if Disclosure of Legal Proceedings Is Required Pursuant to Item 2(d) or 2(e) o
	6	Citizenship or Place of Organization Federal Republic of Germany
Number of Shares Beneficially Owned by Each Reporting Person With			7	Sole Voting Power 14,757,258
			8	Shared Voting Power -0-
			9	Sole Dispositive Power 14,757,258
			10	Shared Dispositive Power -0-
	11	Aggregate Amount Beneficially Owned by Each Reporting Person 14,757,258
	12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares o
	13	Percent of Class Represented by Amount in Row (11) 10.46%*
	14	Type of Reporting Person CO

*  Based on 141,056,498 share of the Issuer’s common stock outstanding as of January 31, 2018 as reported in the Issuer’s Annual Report on Form 10-K for its fiscal year ended December 31, 2017.

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Item 1.Security and Issuer.

The class of securities to which this Statement relates is the Common Stock, par value $0.10 per share (the “Common Stock”), of USG Corporation, a Delaware corporation (the “Issuer”). The principal business address of the Issuer is 550 West Adams Street, Chicago, Illinois 60661-3676.

Item 2.Identity and Background.

The persons filing this Statement (collectively, the “Reporting Persons”) are Gebr. Knauf KG, a limited partnership organized under the laws of the Federal Republic of Germany (“Gebr. Knauf”), and C&G Verwaltungs GmbH, a limited liability company organized under the laws of the Federal Republic of Germany (“C & G Verwaltungs”). Gebr. Knauf is owned and controlled by members of the Knauf family. C&G Verwaltungs is an indirect subsidiary of Gebr. Knauf. The principal business address of each of the Reporting Persons and each of the members of the Knauf family is Am Bahnhof 7, 97346 Iphofen, Federal Republic of Germany. The principal business of each of the Reporting Persons is acting as a holding company.

The names of the general partners of Gebr. Knauf are Alexander Knauf and Manfred Grundke.  The names of the general managers of C&G Verwaltungs are Alexander Knauf and Martin Stürmer.  The principal occupation or employment of each of the foregoing individuals is as a managing partner or managing director of various corporations and other entities owned and controlled by the members of the Knauf family. The principal business address of each of the foregoing individuals is Am Bahnhof 7, 97346 Iphofen, Federal Republic of Germany. Each of the foregoing individuals is a German citizen.

During the last five years, neither of the Reporting Persons nor any of their respective general partners or general managers identified in this Statement has been convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors). During the last five years, neither of the Reporting Persons nor any of their respective general partners or general managers identified in this Statement was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3.Source and Amount of Funds or Other Consideration.

The Reporting Person used funds included in its working capital to acquire the Common Stock to which this Statement relates.

Item 4.Purpose of Transaction.

The Reporting Persons and their affiliates have been stockholders of the Issuer since October 2000.

From time to time over the years, representatives of Gebr. Knauf have met with the senior management of the Issuer to discuss Gebr. Knauf’s potential interest in an additional investment or acquisition transaction involving the Issuer.

On November 28, 2017, Gebr. Knauf delivered an indicative and non-binding proposal to the Chairman of the Board of Directors and the President and Chief Executive Officer of the Issuer providing for the acquisition of 100% of the outstanding shares of the Issuer at a price of $40.10 per share.  A copy of Gebr. Knauf’s letter is attached as Exhibit 99.1 and is incorporated herein by reference.  The Issuer on December 20, 2017 provided a written response indicating that its Board of Directors, in consultation with its financial and legal advisors, had considered Gebr. Knauf’s proposal and had determined that it was not in the interest of the Issuer’s stockholders to enter into discussions with Gebr. Knauf regarding its proposal.

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Following the release of the Issuer’s 2017 annual report and its March 8, 2018 investors day presentation, Gebr. Knauf on March 15, 2018 delivered a revised indicative and non-binding proposal to the Issuer providing for the acquisition of 100% of the outstanding shares of the Issuer at a price of $42 per share. A copy of Gebr. Knauf’s revised proposal letter is attached as Exhibit 99.2 and is incorporated herein by reference.  Gebr. Knauf is presently awaiting the Issuer’s response to its revised proposal.

At the request of Berkshire Hathaway, Inc. (“Berkshire”), on March 23, 2018, senior representatives of Gebr. Knauf and representatives of its financial advisor held a telephonic discussion the Chief Executive Officer and another senior executive of Berkshire. Berkshire, together with its affiliates, is the largest stockholder of the Issuer. During the call, Berkshire proposed to grant Gebr. Knauf an option to purchase all of the shares of the Issuer held by Berkshire and its affiliates.  The option would be exercisable only in connection with the consummation of the purchase by Knauf of all of the outstanding shares of the Issuer at a price of not less than $42 per share. The option exercise price payable to Berkshire would be the same price paid to the other stockholders of the Issuer by Gebr. Knauf, less an option purchase price of $2 per share to be paid by Gebr. Knauf to Berkshire upon the grant of the option. Berkshire stated that its proposal was subject to legal review. Gebr. Knauf is currently evaluating Berkshire’s option proposal.

There are no agreements, written or otherwise, between Gebr. Knauf and Berkshire or their respective affiliates with respect to the proposals made by Gebr. Knauf to the Issuer or relating to the option arrangement proposed by Berkshire. The Reporting Persons are not able to anticipate whether the Issuer will respond favorably to its revised proposal. There can be no assurance that the transactions contemplated by Gebr. Knauf’s revised proposal will be consummated or that the terms of any transaction involving the Issuer that may be consummated will not differ materially from the terms contemplated by the revised proposal.

The Reporting Persons will continue to evaluate their investment in the Issuer on the basis of various factors, including the Issuer’s business, financial condition, results of operations and prospects, general economic and industry conditions, and the securities markets in general and those for the Issuer’s shares. Based upon such evaluation, the Reporting Persons may take such actions in the future as they may deem appropriate in light of the circumstances existing from time to time. Depending on market and other factors, the Reporting Persons may seek to acquire additional shares of Common Stock in the open market or in private transactions, or determine to dispose of all or a portion of the Common Stock beneficially owned by the Reporting Persons, including through hedging transactions with third parties.  Except as set forth in this Item 4, the Reporting Persons do not have any plans or proposals with respect to any of the actions specified in clauses (a) through (j) of Item 4 of Schedule 13D.

Item 5.Interest in Securities of the Issuer.

(a)-(b)   The Reporting Persons beneficially own 14,757,258 shares of Common Stock, representing 10.46% of the outstanding shares of Common Stock.  The percentage beneficial ownership of the Reporting Persons has been determined based on 141,056,498 share of Common Stock outstanding as of January 31, 2018 as reported in the Issuer’s Annual Report on Form 10-K for its fiscal year ended December 31, 2017.  The Reporting Persons have sole power to vote or direct the voting of, and sole power to dispose or direct the disposition of, the 14,757,258 shares of Common Stock they beneficially own.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

(c) — (e)  Not Applicable.

Item 7.Material to Be Filed as Exhibits.

99.1Non-Binding Proposal Letter dated November 28, 2017.

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99.2Revised Non-Binding Proposal Letter dated March 15, 2018.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

March 26, 2018

GEBR. KNAUF KG

/s/ Alexander Knauf

Alexander Knauf

General Partner

C & G VERWALTUNGS GMBH

/s/ Alexander Knauf

Alexander Knauf

General Manager

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EX-99.1

Exhibit 99.1

[Gebr. Knauf KG Letterhead]

PRIVATE AND CONFIDENTIAL

November 28, 2017

Jennifer F. Scanlon

President and Chief Executive Officer and Member of the Board of Directors

cc: Steven F. Leer, Chairman of the Board of Directors

USG Corporation
550 West Adams Street

Chicago, Illinois 60661

Dear Jennifer:

On behalf of Gebr. Knauf KG (“Knauf”), we are pleased to submit this non-binding indication of interest for the acquisition of 100% of the outstanding shares of USG Corporation (“USG” or the “Company”) (the “Transaction”). We believe there is compelling strategic logic to such a combination and that Knauf would provide the best possible custodian to ensure the long term success of USG’s operations, brand and people. We are prepared to pay an attractive price in cash in order to effect the Transaction.

1.Strategic Rationale

We have been a committed and supportive shareholder in USG for many years. We have always been convinced of the strong strategic merits of a closer cooperation or combination and have devoted significant resources to study this in detail.

As you know, Knauf is an internationally operating family-owned company headquartered in the city of Iphofen, Germany with net sales in excess of $ 8 billion and EBITDA in excess of $1.6 billion. Knauf’s long term vision is to become a leading global building products company. In line with this vision, we have continued in recent years to expand our businesses both organically and through acquisitions and have invested $ 3 billion in the last five years alone. We are now seeking additional opportunities to further accelerate our geographical diversification as well as revenue and profit growth. Combining the leading Wallboard Producers in our respective North American and European markets to create a global leader in our industry is a critical step towards achieving this goal.

We believe a combination of Knauf and USG would offer the combined entity the ability to meet customer needs better than either company would be able to achieve on its own. Our businesses, products, and global footprint are highly complementary and, in particular, Knauf would strengthen USG’s position outside the U.S. Together we can

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provide a broad range of building products to a well-balanced geographical and end market customer base. The integration of our platforms, knowledge sharing and continued investment will allow us to establish an optimized manufacturing, sales, capex and R&D structure on a global scale:

·In North America, an integration of Knauf’s Insulation division in the medium term would form a leading light building materials provider

·In Latin America, Knauf’s broad geographical coverage and scalable production facilities will be an ideal growth platform for USG Ceilings and our entire Latin American business is intended to be fully integrated with USG in the medium term

·In Asia, Knauf’s plant network is highly complementary to that of USG Boral JV and a combination would strengthen the position against upcoming Chinese and Japanese competition. We are highly supportive of the JV and open to discussions to enable further growth, including a future acquisition of a 100% interest in the JV

2.Purchase Price / Form of Consideration

Based on our review of publicly available information, we propose to acquire 100% of USG’s outstanding common shares at a cash purchase price of $40.1 per share. The aggregate equity and transaction values implied by our proposal total $ 5.8 billion and $ 6.6 billion, respectively. This all-cash proposal provides USG shareholders with substantial and immediate cash-certain value representing:

·an attractive multiple of 10.7x 2017E EBITDA (based on average research consensus estimates), which we believe is very compelling relative to precedent transactions in our industry

·a premium of 12.3% to USG’s highest closing share price over the last 52 weeks ($35.71 reached on November 24, 2017) which is also close to being USG’s all-time high closing share price since the 2008 financial crisis ($35.85)

·value in excess of any 12-month price targets by research analysts

The proposal is based on 144.1 million net diluted shares outstanding and $846 million of net debt (including pension / OPEB obligations) as of September 30, 2017 and amongst other things assumes that the Company’s public disclosure is an accurate reflection of the state of operations and potential liabilities.

3.Financing

The Transaction will not be subject to any financing condition. We expect to finance the Transaction (and any USG debt to be refinanced) from existing corporate funds and additional borrowings. We have significant cash reserves readily available and would arrange additional financing through banks for which we have attached a highly confident letter from Morgan Stanley for up to $4.0 billion in debt financing. We intend to prepare and deliver fully committed financing by the time of the signing of definitive agreements.

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4.Approach to Integration, Heritage and Employees

As evidenced by our long history and successful international expansion, Knauf has a strong culture of attracting and retaining key managers and employees. We believe that USG management and employees would be critical to the integration of our businesses and the achievement of our long-term success. This Transaction is not predicated on job cuts or plant closures. Rather, we plan to invest in the people at USG and anticipate that there will be attractive career opportunities at the combined company for them. At the appropriate time, we look forward to discussing ensuring retention of key talent.

We plan to preserve and strengthen USG’s Chicago headquarters to become Knauf’s main management hub in the Americas, including our existing North American Insulation and Latin American Gypsum operations. Likewise, we have long admired USG’s strong brand name and reputation in the marketplace, which we would envision to preserve and build upon.

5.Ability to Expeditiously Work to a Binding Proposal; Advisors

We and our advisors have already completed extensive analysis and preliminary due diligence on USG based on publicly available information. Our proposal is subject to having the opportunity to conduct certain due diligence related to USG’s business, financial plans and activities. This will include gaining further clarity on the UBBP JV with Boral and intentions relative to change of control implications. We are highly supportive of the JV but are open to dialogue on alternatives. Key areas of our due diligence focus are enclosed with this letter.

Consistent with a public company due diligence process and with the need to preserve utmost confidentiality, we are prepared to proceed expeditiously and believe, with adequate access to necessary information, we could be in a position to complete our due diligence within weeks. To expedite matters, we are prepared to begin negotiating definitive transaction documentation during the pendency of our due diligence investigation.

In light of the significant resources and time we already have and will continue to devote to this effort, we would like to request a short period of exclusivity allowing both parties to move forward in a focused and expeditious manner.

We have engaged Morgan Stanley as our financial advisor, Baker McKenzie as our legal advisor and PricewaterhouseCoopers as our accounting and tax advisor.

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6.Approvals and Conditions

This non-binding indication of interest is made by the General Partners of Knauf. We have reviewed the Transaction with our board (“Gesellschafterausschuss”) and all family shareholders, who are highly supportive.

Entry into a definitive Transaction would be subject to customary terms and conditions, including: (a) completion of satisfactory due diligence, (b) negotiation of mutually acceptable definitive agreements typical for transactions of this type, and (c) approval by the parties’ respective boards of directors of the final terms and conditions of the Transaction.

We would expect the consummation of a Transaction to be subject to customary closing conditions including regulatory and USG shareholder approvals. Together with outside counsel, we have reviewed the potential combination of our businesses from a regulatory standpoint and believe that the Transaction would not raise material issues. We are highly committed to the successful completion of this Transaction and would like to engage with you and your counsel as soon as possible to jointly finalize our regulatory analysis.

7.Confidentiality

This indication of interest is being made confidentially to you. We do not intend to make this letter or the existence of our proposal public, and expect that you will not issue any press release or other public announcement and not make any disclosure to any person (other than your board members, advisors and Berkshire Hathaway) relating to this proposal or the transactions contemplated hereby without our prior knowledge and written consent. A premature publication or leak may lead to the immediate withdrawal of our proposal.

We hope that you and your Board of Directors share our enthusiasm about this Transaction. This matter is of the highest priority for us, and we are committed to working together with you to bring this vision to fruition. We appreciate your timely consideration of this proposal and look forward to your response and discussing the next steps towards the Transaction. Please feel free to contact us in the interim with any questions or clarification you may require.

Very truly yours,

Alexander Knauf	Manfred Grundke
General Partner	General Partner
Gebr. Knauf KG	Gebr. Knauf KG

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Appendix A: Key Due Diligence Focus Areas

We would expect to receive the opportunity to undertake a full due diligence on the Target with the assistance of our professional advisers prior to the signing of the transaction, including but not limited to access to a customary virtual data room.

We have experience in conducting similar due diligence investigations and can confirm that we can complete such due diligence exercise within the usual timeframe.

Please find below a summary of key due diligence focus areas; a comprehensive due diligence list can be provided upon request.

1.Strategy Review & Business Plan

1.1.Business plan and projected financial statements

1.2.Volume and pricing trends and outlook by region / product / customers

1.3.Impact of L&W divestment including dealer structure (price/mix/volume effect)

2.Accounting and Financials

2.1.Detailed revenue breakdown and profitability by product / group and customers

2.2.Cost breakdown / impact of raw material price fluctuations and ability to pass-through

2.3.Quality of earnings

2.4.Historical level of investment; maintenance, growth and R&D capex

3.UBBP Joint-Venture

3.1.Business plan including key assumptions and risks

3.2.Existing earn-out terms/conditions/targets within UBBP JV agreement

3.3.Any liabilities (including off-balance sheet) at the joint-venture level

3.4.Material contracts and agreements affected by a change of control

4.Commercial Operations / Engineering / HSE

4.1.OEE performance, capacity utilization and debottlenecking initiatives

4.2.Volume, coverage and quality of owned or leased gypsum rock quarries

4.3.Material supply and off-take contracts

4.4.Quality control and claims

5.Customary Corporate Organization, Governance and Reporting

6.Legal and Anti-Trust Due Diligence

6.1.Historical and outstanding litigation, administrative or arbitration (incl asbestos claims)

6.2.Material contracts and agreements affected by a change of control

6.3.Asbestos personal injury trust

6.4.Agreements relating to any acquisitions (especially CeilingsPlus) or disposals

7.Intellectual Property & R&D

8.Tax & Insurance

8.1.Net operating losses

8.2.Historical claims

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EX-99.2

Exhibit 99.2

[Gebr. Knauf KG Letterhead]

PRIVATE AND CONFIDENTIAL

March 15, 2018

Steven F. Leer

Chairman of the Board of Directors

Jennifer F. Scanlon

President and Chief Executive Officer and Member of the Board of Directors

USG Corporation
550 West Adams Street

Chicago, Illinois 60661

Dear Steven and Jenny:

As previewed at our meeting in New York earlier this week and further to our proposal letter dated November 29, 2017 (which we re-attach for convenience), we are writing on behalf of Gebr. Knauf KG (“Knauf”) to submit a revised indicative and non-binding proposal for the acquisition of 100% of the outstanding shares of USG Corporation (“USG” or the “Company”) (the “Transaction”).

We continue to believe there is compelling strategic logic to our proposed Transaction and that Knauf would provide the best possible custodian to ensure the long term success of USG’s operations, brand and people.  We are unwavering in our focus to bring this Transaction to fruition and continue to believe we are offering an attractive cash-certain price.

As a result, we were disappointed by your letter dated December 20, 2017 and USG’s refusal expressed on our subsequent phone call to engage in further transaction discussions with us.  Following our phone call in December, as you suggested, we have awaited and reviewed your 2017 annual report and attended your investor day on March 8th.  We have carefully considered the additional data provided in these forums along with the various valuation comments you had made on our phone call.

As we communicated in our November meeting, we are not opportunistic in our timing relative to daily share prices but rather focused on what we believe to be the sustainable long-term value of the business.  As a leading global building products company and

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having been invested in USG for almost two decades, we both know that at the heart of the matter this is a mature and cyclical industry.

Revised Proposal Terms

Based on our conversation in New York, we are willing to increase our price in order to demonstrate our seriousness and our desire to move forward with a Transaction that delivers full and fair value to all shareholders.

We propose to acquire 100% of USG’s outstanding common shares at a cash purchase price of $42.00 per share which provides USG shareholders with risk-free, substantial and immediate cash-certain value representing:

·an attractive multiple of 11.2x 2017 fully adjusted EBITDA, which we believe is very compelling relative to precedent transactions in our industry

·a premium of 21% to USG’s volume weighted average price since USG’s release of full-year results ($34.63) and 30% to the 12-months average price ($32.36), both based on closing prices as of March 14, 2018

·value in excess of the highest closing share price over the last decade and since the global financial crisis ($40.82 reached on January 8, 2018)

Our proposal is based on our review of publicly available information.  We remain ready and willing to engage in discussions to explore further potential pockets of value with the benefit of access to non-public information as part of our focused due diligence with minimal disruption to the USG organization.

Other aspects of our proposal (as further detailed in our November letter) are:

·Strong strategic rationale

·Good custodian for the business with thoughtful approach to integration, employment opportunities and preservation of heritage

·Strong ability to consummate a transaction including financing certainty and a smooth pathway to all required approvals

Next Steps

We strongly prefer to conduct our discussions with you privately and are eager to meet with you at your earliest convenience to discuss next steps.  We and our advisors (Morgan Stanley, Baker McKenzie, PricewaterhouseCoopers) stand ready to commence focused due diligence immediately.

This revised proposal presents an immediate high-value cash-certain monetization opportunity for USG shareholders that de-risks any future business plan execution and cyclicality while creating a stronger company.  We are convinced that our offer is highly attractive and will win the approval of at least 80% of the company owners.

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As you know, we have been patient and supportive of USG management and have always voted with USG’s management and board, even during challenging times over the years.  Should you choose not to engage in good faith discussions with us we may reconsider our behaviour.

We appreciate your timely consideration of this revised proposal and look forward to your response.  Please feel free to contact us in the interim with any questions or clarification you may require.

Very truly yours,

Alexander Knauf	Manfred Grundke
General Partner	General Partner
Gebr. Knauf KG	Gebr. Knauf KG

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