| Variables | Label | Definition |
| R&D intensity | R&D | R&D spending/total sales |
| Capital structure | DA | Debt/asset |
| Profitability | ROA | Net income/asset |
| Growth | Grow | Net income(t)-NI(t − 1)/NI(t − 1) |
| Firm size | Lnsale | Ln(sale) |
| Non-debt tax shield | Shield | Depreciation + amortization /total asset |
| Collateral | Collateral | Net fixed asset/total asset |
| Tradable shares | Tra | Tradable: D = 1, otherwise, D = 0 |