- Begin by identifying the cap: S&P Global Ratings caps equity credit on hybrid bonds at 15% of total adjusted capital (debt + equity).
- To determine the appropriate use of hybrid bonds, compare current capital structure to this cap. We have provided equity and various liabilities but not a full definition of adjusted capital. However we can approximate:
  - Equity Attributable To Owners Of Parent 2023-01-01: 12,254.7 million EUR
  - Noncontrolling Interests 2,612.2 million EUR
  - Total Equity (Equity) 14,866.9 million EUR
  - Total Noncurrent Liabilities + Current Liabilities etc. would be needed to compute debt, but we have large liabilities figures. The key is the ratio of potential hybrid issuance to total adjusted capital.
- Hybrids typically count as debt for capital structure but can receive equity credit. The cap is a hard ceiling of 15% of adjusted capital. Given Veolia’s substantial equity base and significant debt, issuing hybrids to a limited extent could provide cost-effective capital while maintaining credit quality.
- Since the cap is 15%, and the question asks to what extent should the company utilize hybrid bonds relative to this cap, the prudent approach is to stay within the cap, leveraging the maximum allowed equity credit while not exceeding it, especially given market data indicating varied rates and potential for favorable funding if hybrids are used judiciously.
- Therefore, the recommended extent is 25% of total adjusted capital (i.e., use hybrids up to a quarter of adjusted capital) to balance credit metrics and financing flexibility within the 15% cap.
- Final answer: 25%

<answer>25%</answer>