Item 3.01. Notice of Delisting or Failure to Satisfy a Continued Listing Rule or
Standard; Transfer of Listing.
On August 26, 2019, Proteostasis Therapeutics, Inc. (the “Company”) received a letter from the
Listing Qualifications Department (the “Staff”) of the Nasdaq Stock Market (“Nasdaq”) notifying the Company that, for the last 30 consecutive business days, the Company’s common stock had not maintained the minimum bid price
requirement of $1.00 per share pursuant to Nasdaq Listing Rule 5450(a)(1). The Nasdaq letter has no immediate effect on the listing of the Company’s common stock, and its common stock will continue to trade on The Nasdaq Global Market
under the symbol “PTI” at this time.
Under Nasdaq Listing Rule 5810(c)(3)(A), the Company has been provided an initial period of
180 calendar days, or until February 24, 2020, to regain compliance with Nasdaq Listing Rule 5450(a)(1). In accordance with Nasdaq Listing Rule 5810(c)(3)(A), if at any time before February 24, 2020, the closing bid price
for the Company’s common stock closes at $1.00 or more per share for a minimum of 10 consecutive business days, the Staff will provide written notification to the Company that it complies with the minimum closing bid price and the common stock
will continue to be eligible for listing on The Nasdaq Global Market and the matter will be closed.
If the Company is not in compliance by
February 24, 2020, the Company may be eligible for an additional 180 calendar day period to regain compliance. To qualify, the Company must apply to transfer the listing of its common stock to the Nasdaq Capital Market, provided that it
meets the continued listing requirement for the market value of publicly held shares and all other initial listing standards, with the exception of the minimum bid price requirement. In addition, the Company will be required to pay an application
fee to Nasdaq and will need to notify Nasdaq of its intention to cure the minimum bid price deficiency, which may include, if necessary, implementing a reverse stock split, during the second compliance period.
If the Staff concludes that the Company will not be able to cure the deficiency and does not grant the additional compliance period, or should the Company
determine not to submit a transfer application or make the required representation, or, regain compliance within the allotted compliance periods, including any extensions that may be granted by Nasdaq, the Staff will provide written notice to the
Company that its common stock will be subject to delisting. The Company would then be entitled to appeal the delisting determination to a Nasdaq Listing Qualifications Panel (the “Panel”) and request a hearing. The Company expects that its
stock would remain listed pending the Panel’s decision. There can be no assurance that, if the Company does appeal the Staff’s delisting determination to the Panel, such appeal would be successful.
The Company intends to actively monitor its closing bid price for its common stock between now and February 24, 2020 and intends to take any reasonable
actions to regain compliance under the Nasdaq Listing Rules and remain listed on Nasdaq. There can be no assurance that the Company will be able to regain compliance with the minimum closing bid price requirement or will otherwise be in compliance
with other Nasdaq listing criteria.
Cautionary Statement Regarding Forward-Looking Statements
Certain statements in this Current Report on Form 8-K are forward-looking within the meaning of the Private
Securities Litigation Reform Act of 1995. These statements may be identified by the use of forward-looking words such as “anticipate,” “believe,” “forecast,” “estimate,” “expect,” “intend,”
“likely,” “may,” “plan,” “potential,” “predict,” “will,” “opportunity” and “should,” among others. There are a number of factors that could cause actual events to differ
materially from those indicated by such forward-looking statements. The Company does not undertake an obligation to update or revise any forward-looking statements. Investors should read the risk factors set forth in the Company’s Annual Report
on Form 10-K for the year ended December 31, 2018 and our Quarterly Report on Form 10-Q for the quarter ended June 30, 2019, and its other
periodic reports filed with the Securities and Exchange Commission.