The SEC in December suspended trading in the companies' shares for delinquent reporting, to protect investors by preventing stock manipulation. The agency said the companies' failure to submit the quarterly and annual reports on time means the public has a lack of current and accurate information about them.

The SEC suspended trading in 26 other small companies last June for the same reason.

Most of the companies' shares are traded on the National Association of Securities Dealers' OTC Bulletin Board, an electronic trading system for small stocks that are thinly traded.

In the proceedings started Tuesday, hearings will be held before an administrative law judge at the SEC who will decide whether the companies' registration to issue securities should be suspended or revoked.

The company operating the site named for Koop, DrKoop.Com Inc., was once worth more than $1 billion but collapsed a few years after going public. Some of its assets, notably Internet domain names, were sold in bankruptcy court for $186,000 to vitamin retailer Vitacost.com Inc. in 2002.

Koop was paid $10,000 for the right to use his name on the site.

The other companies are: 1st Miracle Entertainment Inc., Advanced Solutions and Technologies Inc., Amitelo Communications Inc., Comparator Systems Corp., Emerging Enterprise Solutions Inc., Shaman Pharmaceuticals Inc., United States Crude International Inc. and Whitehall Enterprises Inc.