Securities industry regulators have dropped all charges against former star technology banker Frank Quattrone over how his investment bank allocated shares of hot stocks during the late-1990s Internet boom.

The ruling Wednesday by a hearing officer of the National Association of Securities Dealers, the brokerage industry’s self-policing organization, was the third in a trio of legal victories for Quattrone. In March, the Securities and Exchange Commission overturned a lifetime ban from the industry against Quattrone, and his conviction on charges of obstructing justice was thrown out by a federal appeals court.