Exhibit 99.4

August 1, 2016

Dear

I’m thrilled to announce that SolarCity entered into a contract to combine with Tesla in a transaction that would create the world’s only integrated provider of clean energy, storage and transportation.

We’re incredibly excited about what this combination with Tesla offers for our company and the future of sustainable energy. In ten short years, we’ve created the number one solar power provider in America. Now, as we move to introduce a range of new product offerings that we hope will revolutionize the aesthetics, affordability and performance of solar power and battery storage, we are aligning with what we consider to be the most innovative manufacturer and product developer in the world.

As one company, Tesla (storage) and SolarCity (solar) can create fully integrated residential, commercial and grid-scale products that improve the way that energy is generated, stored and consumed. By joining forces, we can operate more efficiently and fully integrate our products, while providing customers with an aesthetically beautiful and simple one-stop solar + storage experience: one installation, one service contract, one phone app.

You have and will continue to play a vital role in our success. With today’s announcement we look forward to building on our relationship with you so we can continue serving our customers.

Until the transaction closes, SolarCity and Tesla will continue to operate as independent companies, as we always have. It’ll be business as usual at SolarCity.

We’ll provide you with any relevant updates as we move forward. As always, if you have any questions, please don’t hesitate to contact us.

We hope you share our enthusiasm about this exciting transaction and we sincerely thank you for your continued support. We look forward to taking the next step in the future of sustainable energy together with you.

Sincerely,

Lyndon Rive

Co-Founder, CEO

Forward Looking Statements

Certain statements in this material, including statements relating to the proposed combination of SolarCity Corporation (“SolarCity”) and Tesla Motors, Inc. (“Tesla”) and the combined company’s future financial condition, performance and operating results, strategy and plans are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to numerous assumptions, risks and uncertainties which change over time. Forward-looking statements speak only as of the date they are made and we assume no duty to update forward-looking statements. In addition to factors previously disclosed in Tesla’s and SolarCity’s reports filed with the U.S. Securities and Exchange Commission (the “SEC”) and those identified elsewhere in this presentation, the following factors, among others, could cause actual results to differ materially from forward-looking statements and historical performance: the ability to obtain regulatory approvals and meet other closing conditions to the transaction, including requisite approval by Tesla and SolarCity stockholders, on a timely basis or at all; delay in closing the transaction; the ultimate outcome and results of integrating the operations of Tesla and SolarCity and the ultimate ability to realize synergies and other benefits; business disruption following the transaction; the availability and access, in general, of funds to meet debt obligations and to fund ongoing operations and necessary capital expenditures; and the ability to comply with all covenants in the indentures and credit facilities of Tesla and SolarCity, any violation of which, if not cured in a timely manner, could trigger a default of our other obligations under cross-default provisions.

The foregoing review of important factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included herein and elsewhere, including the Risk Factors included in Tesla’s and SolarCity’s most recent reports on Form 10-K and Form 10-Q and other documents of Tesla and SolarCity on file with the Securities and Exchange Commission. Tesla’s and SolarCity’s SEC filings are available publicly on the SEC’s website at www.sec.gov. Any forward-looking statements made or incorporated by reference herein are qualified in their entirety by these cautionary statements, and there can be no assurance that the actual results or developments anticipated by us will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, us or our business or operations. Except to the extent required by applicable law, Tesla and SolarCity undertake no obligation to update publicly or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

No Offer or Solicitation

This document does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Important Additional Information and Where To Find It

The proposed transaction will be submitted to the stockholders of each of SolarCity and Tesla for their consideration. Tesla will file with the SEC a Registration Statement on Form S-4 that will include a joint proxy statement/prospectus of SolarCity and Tesla. Each of SolarCity and Tesla will provide the joint proxy statement/prospectus to their respective shareholders. SolarCity and Tesla also plan to file other documents with the SEC regarding the proposed transaction. This document is not a substitute for any prospectus, proxy statement or any other document which SolarCity or Tesla may file with the SEC in connection with the proposed transaction. INVESTORS AND SECURITY HOLDERS OF SOLARCITY AND TESLA ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT WILL BE FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. You may obtain copies of all documents filed with the SEC regarding this transaction, free of charge, at the SEC’s website, www.sec.gov.

Participants in the Solicitation

SolarCity, Tesla, and certain of their respective directors, executive officers and other members of management and employees, under SEC rules may be deemed to be participants in the solicitation of proxies from SolarCity and Tesla stockholders in connection with the proposed transaction. Information regarding the interests of the persons who may, under the rules of the SEC, be deemed participants in the solicitation of SolarCity and Tesla stockholders in connection with the proposed transaction will be set forth in the joint proxy statement/prospectus when it is filed with the SEC. You can find more detailed information about SolarCity’s executive officers and directors in its definitive proxy statement filed with the SEC on April 21, 2016. You can find more detailed information about Tesla’s executive officers and directors in its definitive proxy statement filed with the SEC on April 15, 2016. Additional information about SolarCity’s executive officers and directors and Tesla’s executive officers and directors can be found in the above-referenced Registration Statement on Form S-4 when it becomes available.