These large profits from promotions, under-writings and security purchases led to a revolutionary change in the conduct of our leading banking institutions. It was obvious that control by the investment bankers of the deposits in banks and trust companies was an essential element in their securing these huge profits. And the bank officers naturally asked, "Why then should not the banks and trust companies share in so profitable a field? Why should not they themselves become investment bankers too, with all the new functions incident to 'Big Business'?" To do so would involve a departure from the legitimate sphere of the banking business, which is the making of temporary loans to business concerns. But the temptation was irresistible. The invasion of the investment banker into the banks' field of operation was followed by a counter invasion by the banks into the realm of the investment banker. Most prominent among the banks were the National City and the First National of New York. But theirs was not a hostile invasion. The contending forces met as allies, joined forces to control the business of the country, and to "divide the spoils." The alliance was cemented by voting trusts, by interlocking directorates and by joint ownerships.

There resulted the fullest "cooperation"; and ever more railroads, public service corporations, and industrial concerns were brought into complete subjection.