I need to assess how much of S&P's 15% hybrid equity credit cap TenneT should utilize.

## Key Analysis

### Current Hybrid Position
- Hybrid Capital: €2,125M (constant across both periods)
- Total Equity: €7,713M (2023-01-01)
- Total Debt (Long-term + Short-term borrowings): €19,006M + €709M = €19,715M
- Total Adjusted Capital (Debt + Equity) ≈ €19,715M + €7,713M = €27,428M

### S&P's 15% Cap Calculation
- 15% of Total Adjusted Capital: 0.15 × €27,428M ≈ €4,114M
- Current hybrid capital: €2,125M
- Current utilization: €2,125M / €4,114M ≈ 51.6%

### Factors Supporting Higher Hybrid Utilization

1. **Massive Capital Investment Needs**: TenneT is a transmission system operator with enormous capex (€4,424M in 2022, up from €3,711M). As an energy infrastructure company undergoing significant grid expansion, it needs substantial financing.

2. **Operating Losses**: The company reported operating losses of -€976M and net losses of -€879M in 2022. This puts pressure on equity and retained earnings, making hybrid instruments valuable for maintaining credit metrics.

3. **Rising Debt Levels**: Long-term borrowings surged from €12,366M to €19,006M (54% increase), indicating heavy reliance on debt financing.

4. **Regulated Utility with Stable Cash Flows**: As a regulated TSO, TenneT has predictable revenue streams, which supports the use of hybrid instruments. Rating agencies generally accept hybrid equity credit for such entities.

5. **Equity Injection**: The company received €1,230M in capital contributions, showing shareholder support but also the need for additional capital.

6. **Rising Interest Rates**: The swap curve data shows rates rose dramatically in 2022. Hybrid bonds issued at lower rates provide valuable below-market financing, though new issuances would be more expensive.

7. **Declining Equity Ratio**: Equity/Assets fell from ~23.8% to ~20.0%, suggesting balance sheet leverage is increasing and equity credit from hybrids becomes more important.

### Factors Against Maximum Utilization

1. The company is already at ~52% of the cap, suggesting moderate but not extreme utilization.
2. Higher hybrid utilization means more coupon payments, which are already €57M annually.
3. With significant losses eroding equity, there's a question of whether more hybrid issuance could be absorbed.

### Assessment

TenneT is a regulated utility with enormous investment needs for energy transition (grid expansion, offshore wind connections). It's experiencing significant losses due to regulatory timing mismatches and high energy transmission charges. The company clearly benefits from hybrid instruments for credit metric purposes. Given:

- The massive capex program requiring diverse funding sources
- Operating losses pressuring credit metrics
- Regulated nature providing cash flow predictability suitable for hybrid structures
- The need to maintain investment-grade ratings to access capital markets
- Already at ~52% utilization showing comfort with the instrument

The company should utilize a substantial portion of the cap. Given its infrastructure needs, regulated business model, and balance sheet pressures, it would benefit from utilizing most of the available cap, though perhaps not 100% to maintain some flexibility. However, considering the extreme capital needs and the fact that hybrids help maintain credit ratings critical for a regulated utility accessing massive debt markets, a high utilization makes sense.

The company is at roughly 50% now, but given the trajectory of increasing debt and investment needs, pushing toward higher utilization (75-100%) would be reasonable. The stable, regulated nature of the business and clear need for capital support high utilization.

<answer>75%</answer>