Two from John Kenneth Galbraith's The Great Crash 1929:
"There were still better ways of making money. In principle, New York banks could borrow money from the Federal Reserve bank for 5 per cent and re-lend it in the call market for 12. In practice they did. This was, possibly, the most profitable arbitrage operation of all time."
Margins - the cash which the speculator must supply in addition to the securities to protect the loan and which he must augment if the value of the collateral securities should fall and so lower the protection they provide - are effortlessly calculated and watched. The interest rate moves quickly and easily to keep the supply of funds adjusted to the demand. Wall Street, however, has never been able to express its pride in these arrangements. They are admirable and even wonderful only in relation to the purpose they servie. The purpose is to accommodate the speculator and facilitate speculation. But the purposes cannot be admitted. If Wall Street confessed this purpose, many thousands of moral men and women would have no choice but to condemn it for nurturing an evil thing and call for reform. Margin trading must be defended not on the grounds that it efficiently and ingeniously assists the speculator, but that it encourages the extra trading which changes a thin and anemic market into a thick and healthy one. At best this is a dull by-product and a dubious one. Wall Street, in these matters, is like a lovely and accomplished woman who must wear black cotton stockings, heavy woolen underwear, and parade her knowledge as a cook because, unhappily, her supreme accomplishment is as a harlot.
How you likin' Quiet American? It's on my list.