Reasoning:

ENI appears to have a strong case for making substantial use of hybrids, though not necessarily at the full S&P cap.

Key considerations:

- Balance sheet size and leverage: At year-end 2022, ENI had total assets of €152.1bn, liabilities of €96.9bn, and equity of €55.2bn. Reported equity increased materially from €44.5bn to €55.2bn, supported by strong 2022 profitability.
- Profitability and cash generation: 2022 was very strong, with profit of €14.0bn, operating profit of €17.5bn, and operating cash flow of €17.5bn. This supports financial flexibility and the ability to service hybrid coupons.
- Existing debt burden: Borrowings and lease liabilities remain meaningful. Short-term borrowings, current long-term borrowings, current leases, long-term borrowings, and noncurrent leases total roughly €31.9bn at year-end 2022. Hybrids could help preserve credit metrics by receiving partial equity credit.
- Sector profile: As an integrated oil and gas company, ENI faces cyclicality, commodity price volatility, and energy-transition investment needs. Hybrid capital is useful as a buffer, but excessive reliance could be viewed negatively if it substitutes for balance-sheet discipline.
- Cost environment: Rates rose sharply in 2022. The 5Y, 7Y, and 10Y swap curves moved from near-zero/negative levels to around 1.7%–1.9%, while corporate credit yields also rose. Hybrids became more expensive, especially subordinated instruments. This argues against maximizing issuance purely because the cap is available.
- Prior hybrid/perpetual equity usage: ENI issued perpetual subordinated bonds in prior years, with €3.0bn in 2020 and €2.0bn in 2021 shown in equity movements, and paid coupons in 2021 and 2022. This indicates hybrids are already part of its capital structure and accepted by the company, but also suggests further issuance should be calibrated rather than aggressive.
- S&P cap framing: The cap allows equity credit on hybrids up to 15% of adjusted capital. For a large, investment-grade issuer such as ENI, using a meaningful portion of that capacity can be efficient. However, given strong internal cash flow, substantial reported equity, and higher hybrid costs in 2022, using the entire cap would likely be unnecessary.

Overall, ENI should use hybrids actively as a strategic layer of capital, but below the full S&P cap. A high-but-not-maximum utilization is appropriate.

<answer>75%</answer>