To assess the appropriate utilization of hybrid bonds for ENGIE, we analyze the financial data for the fiscal year ended December 31, 2022:

1.  **Financial Position & Leverage:** ENGIE’s total equity is 39.285 billion EUR. Its borrowings (noncurrent and current) sum to approximately 40.591 billion EUR (28.083 + 12.508), indicating significant debt levels. The "Deeply Subordinated Perpetual Notes" (existing hybrids) stood at 3.393 billion EUR as of year-end 2023.
2.  **Profitability and Cash Flow:** Current Operating Income dropped from 6.9 billion EUR (2021) to 5.3 billion EUR (2022). Profit for the year declined sharply from 3.75 billion EUR to 0.39 billion EUR. The company faced increased finance costs (3.7 billion EUR in 2022 vs 2.06 billion EUR in 2021).
3.  **Capital Intensity:** ENGIE is undergoing significant transition. Investing activities showed high capital expenditure (6.379 billion EUR in property, plant, and equipment purchases). The energy sector currently demands substantial investment in renewables and infrastructure to meet energy transition goals.
4.  **Market Context:** The swap curve (5Y, 7Y, 10Y) showed a significant increase in 2022 compared to 2020-2021, and iBoxx EUR non-financial IG yields have risen to 2.295%. This indicates a higher cost of debt environment, making hybrid instruments an important tool for maintaining rating headroom while funding capital-intensive transitions.
5.  **Assessment:** ENGIE has an existing base of perpetual notes, suggesting they already value this instrument for balance sheet optimization. Given the decline in net profit, rising finance costs, and the need for sustained capital investment in a high-interest-rate environment, the company faces moderate leverage pressure. A 7.5% allocation aligns with a profile that has moderate refinancing/acquisition needs and requires meaningful improvement in adjusted leverage metrics to preserve its credit profile without being in an acute crisis requiring 15% support.

Considering the existing hybrid level (approx. 3.393 billion EUR) and the annual issuance constraint of 3 billion EUR, a target of 7.5% of total adjusted capital represents a balanced approach to supporting the company’s capital structure during this high-investment cycle.

<answer>7.5%</answer>