San Francisco — Do bigger companies tend to corral more business than smaller ones?
That's what figures in today's securities' markets indicate. A research study of investment trends by the Securities Industry Association reported that seven years ago the top 25 brokerage firms in the business accounted for 58.1 percent of the market revenue. In the first six months of 1982, these 25 firms had 76.9 percent of the total income. Most of the first-half increase came from today's top 10 companies, some of which have been acquired (or joined by) non-Wall Street corporate owners.