| Notations | Name of variable | Definitions |
|
| Stock excess return | Stock return minus benchmark portfolio return |
| C | Cash holdings | Cash and short-term investments |
| Beta | Risk of predation | The coefficient on industry returns in a model that regresses firm monthly stock return on market return and industry return. |
| MV | Market value of equity | Market value of equity, equal year-end number of common shares outstanding times stock price |
| E | EBITDA | Earnings before interest & tax plus depreciation and the amortization |
| R&D | Research & development | Research and development expense |
| NA | Net asset | Total assets minus cash and short-term investments |
| L | Leverage | The sum of interest-bearing short-term debt and long-term debt |
| NF | Net Financing | equity issuance plus debt issuance minus debt redemption |
| I | Interest | Interest expense |
| D | Divided | Dividend payment |