Reasoning:

Italgas is a regulated gas-distribution utility with large infrastructure assets, stable operating cash flow, and significant ongoing capex. That type of issuer can often justify some hybrid issuance because hybrids can support credit metrics while avoiding full common-equity dilution.

However, the case for using hybrids up to the full S&P equity-credit cap is not especially strong:

- Leverage is already high: total liabilities were €8.64bn versus equity of €2.39bn at 2023-01-01, and financial debt is substantial.
- Cash declined sharply in 2022, from €1.39bn to €0.45bn, while investing cash flow was deeply negative at about €1.28bn, reflecting heavy capex and acquisitions.
- Operating cash flow fell materially from about €840m to €548m.
- Interest-rate conditions worsened significantly in 2022: euro swap rates rose sharply across 5Y, 7Y, and 10Y tenors, and corporate credit spreads also increased. Hybrid debt would therefore be relatively expensive compared with the prior period.
- Italgas still has strong regulated earnings and improved profit, with profit after tax rising to €436m, but finance costs and future refinancing risk matter in a higher-rate environment.
- Hybrid bonds receive only partial equity credit from S&P and still create cash interest obligations; overuse could be costly and may not be optimal unless the company is under pressure to preserve ratings or fund large acquisitions.

Given these factors, a moderate-to-high utilization is appropriate, but not full utilization. The company has enough leverage and capital-investment needs to benefit from hybrids, yet the high-rate environment and already significant debt burden argue against maximizing the S&P cap. Therefore, 50% of the cap is the most balanced choice.

<answer>50%</answer>