Regulatory Halt

• The "news pending" halt is the most common, and typically involves delays of no more than an hour or two. This gives all traders and investors a chance to digest the associated press release and make informed decisions on a level playing field. Given the rise of electronic trading systems, investors can take comfort in knowing that if one market maker, such as the New York Stock Exchange, halts trading, all other exchanges that may trade the same stock also honor the halt.
  
  

Nonregulatory Halt

• Nonregulatory delays can happen as a matter of logistics, when a trading imbalance occurs if too many people are on either the buy or sell side. This can happen on markets such as the New York Stock Exchange that is composed of market makers who deal with large orders. This does not occur on all-electronic exchanges such as the NASDAQ, which do not have these limitations.
  
  

Trading Suspension

• A trading suspension is usually a more serious matter than a straightforward trading halt. The U.S. Securities and Exchange Commission is charged with maintaining the integrity of the public markets. If one of the companies under its purview is suspected of filing false or misleading information, or if their required annual or quarterly reports are incomplete or not current, the SEC has the authority to act decisively to protect investors. Unless outright fraud is involved, stockholders may not have recourse to recoup their losses when and if the stock resumes trading.
  
  

Delisting

• A significant milestone in any company's existence is when it meets the standards to be listed on one of the major stock exchanges. The company then has the option of instituting an initial public offering to sell shares to investors. If for any reason the company fail to maintain the minimum standards for listing, such as number of available shares, market value and minimum price, the SEC can take action to delist its stock.