I need to analyze whether Veolia Environnement's capital structure should rely on hybrid bonds, and to what extent. Let me examine the data provided.

## Analysis of Hybrid Bonds in Veolia's Capital Structure

### Current Hybrid Bond Position

From the balance sheet data, I can identify the "Titres Super Subordonnes ADuree Indeterminee" (deeply subordinated securities / hybrid bonds):

- 2022-01-01: 2,460,700,000 EUR
- 2023-01-01: 3,496,300,000 EUR

This shows a significant increase of over 42% in hybrid bonds, primarily due to the acquisition of Suez (1,623,900,000 EUR "Contribution Of Hybrid Debt Suez SA").

### Total Equity Analysis

Total Equity:
- 2022-01-01: 12,770,000,000 EUR
- 2023-01-01: 14,866,900,000 EUR

Hybrid bonds as % of total equity:
- 2022: 2,460.7 / 12,770 = 19.3%
- 2023: 3,496.3 / 14,866.9 = 23.5%

### Key Considerations for Hybrid Bond Usage

**Arguments FOR hybrid bonds (up to a point):**

1. **Credit rating optimization**: Hybrid bonds are treated as equity by rating agencies (typically 50-100% equity credit), improving leverage metrics without diluting shareholders

2. **Tax efficiency**: Coupons are typically tax-deductible (unlike dividends), providing tax shield benefits

3. **No dilution**: Unlike equity, hybrid bonds don't dilute existing shareholders

4. **Flexibility**: Deeply subordinated with no maturity date (perpetual), providing long-term capital

5. **Market context**: Rising interest rates in 2022 (swap curves turned positive after years of negative rates) make fixed-rate hybrids relatively more attractive if issued before further rises

**Arguments AGAINST excessive hybrid bond reliance:**

1. **Higher cost than debt**: Hybrid coupons are typically higher than senior debt rates due to subordination

2. **Dividend pusher/stopper risk**: Many hybrids have clauses that restrict dividends if coupons are deferred

3. **Refinancing risk**: Although perpetual, hybrids often have call dates; market conditions at refinancing matter

4. **Complexity**: More complex capital structure can confuse investors

5. **Limited equity credit at high levels**: Rating agencies limit equity credit if hybrids become too large a portion of capital

### Industry Context

Veolia is a utility/environmental services company with:
- Stable, regulated cash flows
- Capital-intensive operations (significant PP&E: ~16.6B EUR in 2023)
- Need for long-term financing to match long-term assets

Utilities typically benefit from moderate hybrid usage (15-30% of equity) to optimize credit ratings without over-complicating capital structure.

### Financial Health Assessment

Looking at key metrics:
- Total Assets grew from 53.1B to 73.3B EUR (38% increase, largely Suez acquisition)
- Equity grew from 12.8B to 14.9B EUR
- Non-current liabilities grew significantly from 16.5B to 29.2B EUR
- Current financial liabilities decreased from 8.6B to 6.5B EUR

The company is already leveraged, with equity representing only ~20% of total assets. Adding too much hybrid debt further increases effective leverage.

### Optimal Level Analysis

Current hybrid-to-equity ratio of ~23.5% is already at the upper end of typical utility practice. 

Key risks of going higher:
- Rating agencies typically give 50% equity credit for hybrids; beyond certain thresholds (often 15-20% of total capitalization), equity credit may be reduced
- The 2022 interest rate environment (rising rates) means new hybrids would be expensive
- The company just absorbed Suez, adding integration complexity; excessive financial engineering adds risk

The sweet spot for hybrid bonds in utility capital structures is typically:
- 10-25% of equity for BBB-rated utilities
- Up to 30% for stronger credits

Given Veolia's BBB-type credit profile, integration risks from Suez, and already elevated hybrid levels (~23.5%), the optimal strategy would be to **maintain or slightly reduce** hybrid dependence rather than increase it.

However, the question asks what extent capital structure *should* rely on hybrid bonds. The current ~25% level appears appropriate and shouldn't be increased further. Given the options (0%, 25%, 50%, 75%, 100%), 25% represents a reasonable target that:
- Provides rating agency equity credit benefits
- Doesn't over-leverage or over-complicate the structure
- Matches utility sector best practices

0% would forgo rating optimization benefits. 50%+ would be excessive for a BBB utility, risking reduced equity credit from agencies and dividend stopper complications.

<answer>25%</answer>