Each of the SEC stock price indexes is a weighted index of weekly closing prices of selected common stocks on the New York Stock Exchange related to the average weekly closing prices of such stocks in 1939. The weights used are the numbers of shares outstanding. Base values are adjusted for changes in outstanding shares whenever necessary. The groups represented include all industries which accounted for at least one percent of either the volume or value of common stock trading on the New York Stock Exchange in 1949. The stocks chosen within each group give a coverage of at least 65% of volume and value of trading in the stocks of each industry in 1949. A more detailed explanation of the methods of computation and a list of stocks in the present series may be obtained upon request. Back data by weeks since January 1939 are also available, as well as monthly and annual averages of the weekly data for major groups.

Round-lot and Odd-1ot Stock Transactions

Total round-lot sales reported in these tables include all stock sales effected in roundlots, but they exclude transactions in rights and warrants. Round-lot transactions are transsactions in the unit of trading or multiples thereof; odd-lot transactions are those involving a number of shares less than the unit of trading. On the New York Stock Exchange, the unit of trading for most stocks is 100 shares, while some less active stocks have a 10-share unit. On the American Stock Exchange, the unit of trading for a given issue may be 100 shares, 50 shares, 25 shares, or 10 shares. Short sales in these tables include only those short sales which are restricted under the rules; "exempt" short sales are included in total sales. The term "members" includes regular and associate exchange members, their firms, and their partners, including special partners.

Total round-lot sales effected on the New York Stock Exchange are consistently larger than the round-lot volume reported on the ticker of that exchange, inasmuch as the ticker or "reported" volume fails to include certain types of round-lot transactions ordinarily amounting to from 5 to 10 percent of round-lot sales on that exchange.

Total round-lot sales on the American Stock Exchange differ from the round-lot volume on that exchange reported on the ticker because the ticker or "reported" volume includes the roundlot sales of rights and warrants and fails to include certain classes of round-lot stock transactions.

On the New York Stock Exchange, the transactions of specialists in the stocks in which they are registered include all round-lot transactions in an issue by a member for his own account or his firm's account while the member was acting as specialist in that issue. Transactions for the odd-lot account are excluded, as are transactions for the member's account in issues other than those in which he was acting as specialist. For specialists who also act as odd-lot dealers in certain issues, round-lot trades for odd-lot accounts are included with round-lot trades of odd-lot dealers in the succeeding item. To obtain total-activity data for odd-lot dealers, it is necessary to combine the odd-lot figures and the odd-lot dealers' round-lot figures from the two New York Stock Exchange tables.

On the American Stock Exchange, round-lot transactions of specialists in the stocks in which they are registered are not directly comparable with the round-lot trades of specialists on the New York Stock Exchange, since on the American Stock Exchange odd-lot transactions are handled solely by specialists, and the round-lot transactions of specialists resulting from such odd-lot transactions are not segregated from the specialists' other round-lot trades.

AU. S. GOVERNMENT PRINTING OFFICE: 1958 -481413