According to Galbraith what four economic flaws led to the depression?

One of the four economic flaws that led to the depression, according to Galbraith, is the unequal distribution of wealth in the United in the 1920s. The second flaw was not being about to change trading policies when the country became a creditor nation after being a debtor nation. The third flaw was increasing pyramiding of holding companies and the fourth was the immense speculation on the New York Stock Exchange in terms of credit.