From Carret (1930) the twelve commandments of stock speculation are:

1) Never hold fewer than 10 different stocks over 5 fields of business.

2) At least once every 6 months, reappraise every stock you own.

3) Keep at least half your portfolio in dividend paying stocks.

4) Consider dividend yield the least important factor in analyzing any stock.

5) Be quick to take losses and reluctant to take profits.

6) Never put more than 24% of your portfolio into securities about which detailed information is not readily and regularly available.

7) Avoid inside information as you would the plague.

8) Seek facts diligently, advice never.

9) Ignore mechanical formulas.

10) When stocks are high, interest rates rising and business prosperous, at least half a portfolio should be placed in short term bonds.

11) Borrow money sparing, and only when stocks are low, interest rates are low and falling and business depressed.

12) Set aside a moderate proportion of available funds for the purchase of long term options on stocks in promising companies when available.