Tom Irwin, a health foods distributor, called from Culver City, Calif., to say that he lost $20,000 when the stock market plunged because of delays in the sale of the mutual funds that he had inherited from his mother's estate.

A man from Paducah, Ky., complained that he, too, had lost heavily because it took several days for his broker to sell his IBM stock.

Other callers said they were unaware of how risky their investments -- especially in the options area -- were when the market collapsed on Oct. 19.

These callers were among the first 500 people who dialed 1-800-942-9022 yesterday to tell their tales of woe to people manning the new hot line set up by the Northendcol American Securities Administrators Association (NASAA) -- the organization of state officials who regulate the activity of stock brokers within their states.

"The invisible victim of Black Monday and the days since then is the small investor, and there are thousands of them," said James C. Meyer, the president of NASAA, who is also director of the Tennessee Division of Securities.

The NASAA's hot line will operate Monday through Friday from 8 a.m. to 8 p.m. Residents of the District can reach it by telephoning 373-0900.

Halfway through the day yesterday, with calls pouring in, the NASAA officials said they decided to strengthen their operation by bringing in securities examiners from several states to take the calls and apply their expertise.

Meyer said the calls will be turned over to regulators from the home states of the callers, who will advise investors on the actions open to them.

The state regulators also will review the complaints for any indications of fraud or other illegal behavior, he said.

Meyer said NASAA would provide callers with a consumer guide called "Coping With the Crash: A Step-by Step Guide to Investor Rights."

The handbook relates a story of a New Yorker who earns $27,000 a year and was encouraged by his broker to buy stocks "on margin," putting up only 50 percent of the cost of the shares and borrowing the remaining amount.

On Oct. 19, the man faced margin calls of $110,000. On a margin account, if the value of the stock falls, the investor must add additional money to maintain the investment or it will be sold by the brokerage.

"Thousands more stories like these will surface in the coming weeks as investors assess the damage they suffered in the Oct. 19 stock market crash," the NASAA handbook says.

Meyer said that since the market plunge, state regulators had received a wave of phone calls from investors.

The Florida Division of Securities, for instance, has seen its calls from the public almost triple, from 30 a day before Oct. 19 to 80 complaints in a typical post-collapse day, NASAA said.

Meyer noted that a recent U.S. Supreme Court decision will require most disputes between brokers and their customers to go to arbitration, a process that Meyer said "has many serious deficiencies and is in need of reform."

The agreement that most brokerage house customers sign contains a clause in which the customer agrees to take any disputes to arbitration.