ENGIE already uses hybrid capital through its “deeply subordinated perpetual notes,” which stood at €3.393 billion at end-2022, down from €3.767 billion at end-2021. Relative to its balance sheet, this is modest: equity was €39.285 billion, and reported borrowings were €40.591 billion, implying debt plus equity of roughly €79.876 billion before rating-agency adjustments. S&P’s 15% equity-credit cap would therefore be around €12 billion on this simplified basis, far above ENGIE’s existing hybrid stock.

So the question is not whether ENGIE has room under the cap—it clearly does—but whether it should use that room aggressively.

Key considerations:

- Credit support need is meaningful: equity declined from €41.98 billion to €39.285 billion, while noncurrent liabilities rose sharply. Net financial expense worsened to €3.003 billion, and continuing operations produced a loss.
- Cash flow generation remains solid: operating cash flow rose to €8.586 billion, and cash remained high at €15.57 billion.
- Leverage is manageable but not trivial: borrowings are significant, and higher rates increase refinancing costs.
- Market conditions in 2022 became much less favorable for hybrids: 5Y–10Y swap rates rose sharply from near-zero/negative levels to around 1.7%–1.9%, and subordinated non-financial IG spreads rose to about 2.3%. Hybrid issuance would therefore be materially more expensive than in 2020–2021.
- ENGIE is a capital-intensive utility with predictable cash flows, so hybrids can be useful as a rating-supportive funding tool, but overuse would add high coupon burden and refinancing/call risk.

Given these factors, ENGIE should use hybrids meaningfully but not maximize the S&P cap. A moderate-to-high utilization is appropriate: enough to reinforce credit metrics and fund the transition/capex profile, but not so much that it locks in excessive 2022-era hybrid coupons. Among the options, 50% of the cap is the best balance.

<answer>50%</answer>