Enel already uses hybrid bonds materially: equity instruments/perpetual hybrid bonds were €5.567 billion at 2022 year-end, unchanged from the prior year. Relative to its capital structure, this is meaningful but not close to S&P’s maximum equity-credit cap.

Using reported year-end 2022 figures:

- Equity: €42.082 billion  
- Long-term borrowings: €68.191 billion  
- Short-term borrowings: €18.392 billion  
- Current portion of long-term borrowings: €2.835 billion  
- Approximate debt: €89.418 billion  
- Total adjusted capital proxy = debt + equity = €131.500 billion  
- S&P hybrid equity-credit cap at 15% of adjusted capital = about €19.725 billion  
- Existing hybrids = €5.567 billion  
- Existing hybrid use vs cap = €5.567 / €19.725 ≈ 28%

So the current level is closest to 25% of the S&P cap.

From a qualitative standpoint, Enel has reasons to keep some hybrid capacity available rather than fully utilize it: leverage is high, interest rates rose sharply in 2022, finance costs are significant, and earnings were pressured by discontinued operations. However, hybrids remain useful for balance-sheet support because Enel is capital-intensive, has large investment needs, and already has an established hybrid-bond layer. The appropriate level is therefore not zero, but also not aggressive. Among the options, 25% best matches both the current quantitative position and a prudent target relative to S&P’s cap.

<answer>25%</answer>