A Columbus, Ohio, stock brokerage and its president, accused of numerous fraud schemes, were expelled from the National Association of Securities Dealers Wednesday and fined a total of $250,000. Without admitting or denying any wrongdoing, Corna and Co., Inc. and its owner and president, David A. Corna, agreed to the disciplinary action as part of a settlement with the NASD, a self-regulating organization empowered by Congress to oversee the over-the-counter securities market. The firm and Corna were accused of parking securities and making unauthorized trades in clients' accounts ``on hundreds of occasions between 1985 and 1989,'' playing fast and loose with its records _ including creating two bogus customer accounts _ falsifying documents, and not cooperating with an NASD investigation. Parking is an illegal scheme to conceal the true ownership of securities by buying them with the understanding that the original owner will buy them back with no loss to the person they were ``parked'' with. The NASD's Cleveland Business Conduct Committee said ``the conduct at issue represents some of the most serious violations of the federal securities laws and the rules of the Association that can be a committed by a member. ...'' The disciplinary committee also accused Corna of forging the signatures of several customers and former employees. The firm was censured, expelled from membership in the NASD and fined $100,000. Corna also was censured, barred from associating with any NASD member in any capacity and fined $150,000.