Let’s work through the relevant factors systematically.

**1. Financial condition and credit trends (2022 data)**
- Revenue nearly doubled YoY (€143.5B vs €84.5B), but fuel and energy costs exploded from €44.3B to €121.0B.
- Operating profit before D&A swung from +€18.0B to –€5.0B.
- Net loss of €18.2B vs profit of €4.8B in 2021.
- Operating cash flow turned negative: –€7.4B in 2022 vs +€12.6B in 2021.
- Equity dropped from €62.0B to €46.6B.
- S&P Net Debt/EBITDA = –8.22 (implicitly negative EBITDA), FFO/Net Debt = –0.1579.
- Moody’s leverage trend: Deteriorating.

**2. Capital structure and hybrid history**
- EDF has issued hybrids since 2013 and issued in 2021 or 2022.
- There were proceeds from subordinated liabilities of €994M in 2022.
- Payments to hybrid holders were €606M.
- Hybrids are a known part of EDF’s financing toolkit.

**3. Market conditions**
- EUR swap rates rose sharply in 2022 (5Y average 1.73% vs –0.26% in 2021), meaning hybrid issuance is more expensive than in prior years.
- Subordinated spreads also widened (iBoxx sub-sen delta 2.30% avg in 2022 vs 1.30% in 2021), so cost of hybrid vs senior debt is elevated.

**4. Guideline alignment**
- Very high refinancing/funding needs: Negative FOCF, large capex program, significant nuclear provisions.
- Material downgrade risk: Leverage metrics deeply negative, rating likely under severe pressure.
- Hybrid issuance would stabilize adjusted leverage trajectory and help preserve investment grade.
- However, the cost of new hybrids has increased significantly vs existing debt, which argues against the “cost in line with current cost of debt” case for 15%.
- The company already has hybrids outstanding, so 0% is not applicable.

**5. Recommended level**
Given the extreme pressure on credit metrics and high investment needs, EDF clearly needs to optimize its capital structure. However, the substantial increase in hybrid cost relative to historical levels and the fact that the state (owner) can inject equity (as seen with the €3.25B capital increase) suggests that the absolute maximum 15% is not necessary or optimal. A meaningful but not extreme use of hybrids—enough to support metrics without overpaying—fits the 7.5% to 11.25% range. Because hybrid issuance already occurred at around €1B/year and the deterioration is severe, leaning toward the higher end of that band is appropriate.

<answer>11.25%</answer>