UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): April 17, 2017

Power Solutions International, Inc.

(Exact name of registrant as specified in its charter)

201 Mittel Drive, Wood Dale, Illinois 60191

(Address of principal executive offices and zip code)

Registrant’s telephone number, including area code: (630) 350-9400

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On April 17, 2017, Power Solutions International, Inc. (the “Company”) (Nasdaq: PSIX) received a notice from The Nasdaq Stock Market (“Nasdaq”) stating that its Nasdaq Hearings Panel (the “Panel”) had determined to delist the shares of the Company’s common stock from Nasdaq, and accordingly, would suspend trading in the Company’s common stock effective at the open of business on April 19, 2017. The Company has not yet decided whether to request a review of the decision by the Nasdaq Listing and Hearing Review Council. The right to request the review expires on May 1, 2017. Nasdaq will complete the delisting by filing a Form 25-NSE (Notification of Removal from Listing and/or Registration under Section 12(b) of the Securities Exchange Act of 1934) after applicable appeal periods have lapsed.

As previously reported, the Company is not in compliance with Nasdaq Listing Rule 5250(c)(1), which requires listed companies to timely file all required periodic financial reports with the Securities and Exchange Commission (the “SEC”).

Following suspension of trading of the Company’s common stock, the Company’s shares will be quoted on the OTC Pink market electronic quotation service operated by OTC Markets Group Inc. under the trading symbol PSIX. For quotes or additional information on the OTC Pink market, visit http://www.otcmarkets.com.

The Company intends to promptly seek relisting of its common stock on a securities exchange once it has completed the restatement of its financial statements and it is current in its SEC filing obligations.

On April 18, 2017, the Company issued a press release announcing the Panel decision. A copy of the press release is filed herewith as Exhibit 99.1 to this Form 8-K and is incorporated herein by reference.

Quotation of the Company’s common stock on the OTC Pink may result in a less liquid trading market and more volatility in the trading price for the common stock. There can be no assurance that a liquid trading market for the Company’s common stock will develop while it is quoted in the over-the-counter market.

Caution Regarding Forward-Looking Statements

This Form 8-K includes information that constitutes forward-looking statements. Forward-looking statements often address our expected future business and financial performance, and often contain words such as “believe,” “expect,” “anticipate,” “intend,” “plan,” or “will.” By their nature, forward-looking statements address matters that are subject to risks and uncertainties. Any such forward-looking statements may involve risk and uncertainties that could cause actual results to differ materially from any future results encompassed within the forward-looking statements. Factors that could cause or contribute to such differences include: the final results of the Audit Committee’s internal review as it impacts the Company’s accounting, accounting policies and internal control over financial reporting; the reasons giving rise to the resignation of the Company’s former independent registered public accounting firm; the time and effort required to complete the restatement of the affected financial statements and amend the related Form 10-K and Form 10-Q filings; any adverse effects on the Company’s business resulting from Nasdaq’s delisting of the Company’s common stock; the subsequent discovery of additional adjustments to the Company’s previously issued financial statements; the timing of completion of necessary re-audits, interim reviews and audits by the new independent registered public accounting firm; the timing of completion of steps to address and the inability to address and remedy, material weaknesses; the identification of additional material weaknesses or significant deficiencies; the inability to re-list the Company’s common stock on a securities exchange and any delays in obtaining such listing; variances in non-recurring expenses; risks relating to the substantial costs and diversion of personnel’s attention and resources deployed to address the financial reporting and internal control matters and related class action litigation; the impact of the resignation of the Company’s former independent registered public accounting firm on the Company’s relationship with its lender and trade creditors and the potential for defaults and exercise of creditor remedies and the implications of the same for its strategic alternatives process; the impact of the previously disclosed investigation initiated by the SEC and any related or additional governmental investigative or enforcement proceedings; the impact of the resignation of the Company’s CEO; management’s ability to successfully implement the recommendations of the Audit Committee. Actual events or results may differ materially from the Company’s expectations. The Company’s forward-looking statements are presented as of the date hereof. Except as required by law, the Company expressly disclaims any intention or obligation to revise or update any forward-looking statements, whether as a result of new information, future events, changed circumstances or otherwise.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: April 18, 2017