President Reagan has appointed Dillon Read investment banker Nicholas F. Brady to head a commission that will study the stock market collapse and provide recommendations within 60 days. Brady plans to name two other members of the commission and the executive director of its staff by the end of the week.

Securities and Exchange Commission Chairman David Ruder has ordered the SEC to undertake an imm iate study of the causes of the stock market collapse and stock market volatility. He said the study is expected to be completed within 60 days.

Commodity Futures Trading Commission Chairman Kalo Hineman has ordered the CFTC to undertake an immediate study of the causes of the stock market collapse and stock market volatility. The study will have special emphasis on the relationship between trading in stocks and stock index futures and will be completed as soon as possible. The CFTC regulates index futures trading.

The New York Stock Exchange has authorized a study of stock market volatility and the stock market collapse by former IBM general counsel Nicholas deB. Katzenbach, who said he hopes to complete the study by the end of November. The study was launched last spring, before the recent decline in stock prices.

The Chicago Mercantile Exhchange has named a panel of four experts to assist the CME in evaluating the events surrounding the stock market collapse. The members of the panel are Yale economics professor Burton Malkiel, University of Chicago economics professor Merton Miller, Stanford University professor Myron Scholes and Arnold & Porter attorney John O. Hawke Jr. The panel's first meeting will be on Friday; stock index futures contracts are traded on the CME.

Rep. Edward J. Markey (D-Mass.), chairman of the House securities subcommittee, has asked the General Accounting Office to do a study of stock market volatility and the stock market collapse. Markey said he has asked GAO to make recommendations for regulatory changes.