I'll analyze HERA S.P.A.'s financial profile and market conditions to determine the appropriate extent of hybrid bond usage in its capital structure.

**Company Profile:**
- HERA is an Italian multi-utility company (energy, water, waste management) based in Bologna
- Regulated/semi-regulated business with relatively stable cash flows typical of utilities

**Financial Analysis:**

1. **Leverage:** Total debt (noncurrent + current financial liabilities) = €5,689.9M + €650.1M = €6,340M. Equity = €3,644.7M. Debt/Equity ≈ 1.74x - moderately leveraged.

2. **Profitability:** Revenue nearly doubled from €10.6B to €20.1B (energy price driven), but EBIT declined from €611.7M to €533.8M. Net income fell from €372.7M to €305.3M. Margins compressed significantly.

3. **Cash Flow:** Operating cash flow dropped dramatically from €1,045.4M to just €35.7M due to massive working capital deterioration (-€927.6M vs +€47.8M), driven by inventory buildup and receivables growth. This is concerning.

4. **Financing Activity:** The company raised €2,127M in new non-current borrowings in 2022, significantly increasing leverage. Net financing cash flow was +€1,779.5M.

5. **Investment Grade Characteristics:** Utility companies typically maintain investment-grade ratings. HERA has stable regulated assets (intangibles €4.4B, PP&E €1.98B) and goodwill of €848M.

**Hybrid Bond Considerations:**

- **Pros:** Hybrid bonds receive partial equity credit from rating agencies (typically 50%), which could help HERA manage its rising leverage without diluting shareholders. Utilities frequently use hybrids to optimize their capital structure. The rising interest rate environment (swap curves moved significantly higher in 2022) makes pure debt more expensive, and hybrids could provide rating support.

- **Cons:** Hybrid bonds carry higher coupons than senior debt. The company's cash flow generation was very weak in 2022, and adding expensive hybrid instruments could strain coverage ratios. The spread environment (corporate bond spreads and sub-senior delta of ~0.2%) suggests moderate but not extreme cost differentials.

- **Utility sector practice:** Many European utilities use hybrid bonds as a moderate portion of their capital structure (typically 10-25% of total funding) to maintain credit metrics while funding capex.

**Assessment:** HERA has a moderately leveraged balance sheet with significant capex needs and weakening cash flows. Hybrid bonds could be useful as a modest component to support credit metrics, but given the cash flow pressures and already elevated leverage, relying heavily on hybrids (which are more expensive than senior debt) would not be optimal. A moderate allocation of ~25% makes sense — enough to gain rating agency equity credit benefits without excessive cost burden.

<answer>25%</answer>