I need to analyze Iberdrola's capital structure and determine the appropriate reliance on hybrid bonds.

## Key Observations

### Current Hybrid Bond Usage
From the equity statement, I can see references to "Obligaciones Perpetuas Subordinadas" (Perpetual Subordinated Bonds), which are hybrid bonds:
- In 2021-2022, Iberdrola issued €2,740M in perpetual subordinated bonds (classified under non-controlling interests)
- Interest accrued on these was €155M (2021-2022) and €169M (2022-2023)
- The "Instrumentos De Capital Con Caracteristicas De Pasivo Financiero" (Capital instruments with financial liability characteristics) show both current and non-current components: €576M non-current + €87M current = €663M at end of 2022

### Capital Structure Analysis
- **Total Equity**: €58,114M (2022-end)
- **Non-controlling interests**: €16,995M (includes hybrid bonds classified as equity)
- **Total Assets**: €154,667M
- **Non-current financial liabilities**: €44,216M
- **Current financial liabilities**: €25,079M
- **Total debt (financial liabilities)**: ~€69,295M

### Company Profile
Iberdrola is a large utility company with:
- Significant regulated/quasi-regulated assets (€86B+ in PP&E)
- Stable cash flows from operations (€10.4B)
- Investment-grade profile typical of utilities
- Active in capital markets with substantial debt issuance

### Hybrid Bond Rationale
Utilities like Iberdrola commonly use hybrid bonds because:
1. **Rating agency equity credit**: Hybrids typically receive 50% equity credit from rating agencies, helping maintain investment-grade ratings while funding capex
2. **Tax-deductible coupons**: Unlike pure equity, hybrid bond coupons are often tax-deductible
3. **Capital-intensive business**: Large infrastructure investments require diverse funding sources
4. **Iberdrola already uses hybrids**: Evidence of perpetual subordinated bond issuance

### Appropriate Level
Iberdrola already employs hybrid bonds as part of its capital structure. For a utility with ~€69B in financial liabilities and ~€58B in equity:
- Hybrids are a useful but supplementary tool
- Rating agencies typically limit equity credit for hybrids to ~15-20% of total capitalization
- Too much reliance on hybrids would undermine their equity-credit benefit
- The sub-senior delta of ~0.2% (200bps over IG) shows moderate additional cost for subordination

The company's hybrid usage appears moderate — the perpetual subordinated bonds represent a meaningful but not dominant part of their financing. For a company of this size and profile, hybrids should play a supporting role — not zero (they clearly benefit from them) but not majority. A 25% allocation to hybrids in the capital structure is appropriate, reflecting their use as a complementary tool for rating management and tax efficiency without over-reliance.

<answer>25%</answer>