"A price decline is of no real importance to the bona fide investor unless it is either very substantial say, more than a third from cost or unless it reflects a known deterioration of consequence in the company's position. In a well-defined bear market many sound common stocks sell temporarily at extraordinary low prices. It is possible that the investor may then have a paper loss of fully 50 per cent on some of his holdings, without any convincing indication that the underlying values have been permanently affected."