These 2 things are significant:
When can the SEC suspend a stock from trading?
When it serves the public interest and will protect investors, the SEC may suspend trading. For instance, the SEC may act when public information about a company is not current, accurate, or adequate. The SEC has acted when serious questions arose about a company's assets, operations, or other financial information.
Why would the SEC take such action when it knows it will hurt current shareholders?
Because a suspension often causes a dramatic decline in the price of the security, the SEC suspends trading only when it believes the public may be making investment decisions based on false or misleading information. Suspensions give notice to current and potential investors that we have serious concerns about a company. A suspension may prevent potential investors from being victimized by a fraud.