The most actively traded securities in the Stock Exchange Automated Quotation System. About 100 securities came into this category when it was in official use by the London Stock Exchange. These were shares of companies with high turnover and high market capitalization. Alpha stocks had numerous market-makers, and immediate publication of transactions in them required. They were part of a system of categorization that also included beta, gamma, and delta stocks which were those of smaller companies, and less intensively traded.
|Reference: Oxford Press Dictonary of Economics, 5th edt.|