To determine the optimal extent to which VERBUND AG should utilize hybrid bonds relative to the S&P Global Ratings cap, we must analyze the company's financial position, the cost of capital environment, and the strategic benefits of hybrid instruments.

**1. Financial Health and Capital Structure Analysis:**
*   **Equity Position:** As of 2023-01-01, Total Equity is 8,323,019,000 EUR. Equity attributable to owners of the parent is 7,275,986,000 EUR.
*   **Debt Position:**
    *   Noncurrent Financial Liabilities: 2,844,559,000 EUR
    *   Current Financial Liabilities: 1,109,297,000 EUR
    *   Total Financial Debt ≈ 3,953,856,000 EUR.
*   **Leverage:** The debt-to-equity ratio is approximately 0.47 (3.95B / 8.32B). This indicates a relatively conservative capital structure with strong equity backing.
*   **Profitability:** The company is highly profitable, with a Net Profit of 1,948,767,000 EUR in 2022 and an EBITDA of 3,160,679,000 EUR. Interest coverage is robust.

**2. The Role of Hybrid Bonds:**
Hybrid bonds are mezzanine instruments that possess characteristics of both debt and equity. Rating agencies like S&P typically grant "equity credit" (often 50% for strong issuers, up to 100% in specific structural cases, but capped in contribution to total capital) to hybrids. This equity credit improves leverage ratios (Debt/EBITDA, Debt/Capital) without diluting existing shareholders.

**3. S&P Global Ratings Cap Context:**
The prompt specifies a cap where equity credit on hybrids is limited to a maximum of 15% of *total adjusted capital* (Debt + Equity).
*   Total Adjusted Capital ≈ Debt (3.95B) + Equity (8.32B) = 12.27B EUR.
*   15% of 12.27B ≈ 1.84B EUR.
*   This means VERBUND could issue up to ~1.84B EUR in hybrids (assuming 100% equity credit for the sake of the cap calculation logic, or proportionally more if credit is <100%) before hitting the limit where additional hybrids no longer provide rating benefit or might be treated fully as debt.

**4. Market Environment (2022):**
*   **Interest Rates:** The swap curves show a dramatic increase in rates from 2021 to 2022 (e.g., 10Y swap average went from 0.053% to 1.927%).
*   **Credit Spreads:** The iBoxx EUR Non-Financial IG spread increased from 1.298% (2021) to 2.295% (2022).
*   **Cost of Hybrids:** Hybrid coupons are typically set at a spread over the risk-free rate (swap rate) plus a credit spread. With rising rates, the cost of issuing new hybrids in 2022/2023 is significantly higher than in previous years. However, hybrids are still generally cheaper than equity (due to tax deductibility of coupons in some jurisdictions, though often limited for hybrids, and lower required return than equity) and can be cheaper than senior debt if the equity credit allows for a higher rating tier.

**5. Strategic Reasoning for Utilization:**
*   **Rating Optimization:** VERBUND has a strong investment-grade profile. Utilizing hybrids allows the company to optimize its capital structure by boosting the equity base for rating purposes without issuing new shares. This is particularly useful for maintaining a strong credit rating (e.g., A or A-) which lowers the cost of senior debt.
*   **Capacity Headroom:** Given the low current leverage (Debt/Equity < 0.5), the company has significant capacity to take on more mezzanine capital. It is not distressed, nor is it over-leveraged.
*   **Maximizing the Cap:** Since the company is financially strong and the "cap" represents a limit on *beneficial* equity treatment, a company aiming for optimal capital efficiency and rating stability will typically utilize the full allowance of hybrid instruments that receive equity credit. Stopping at 0%, 25%, or 50% of the cap would leave "free" rating benefit on the table. Issuing hybrids up to the cap maximizes the equity buffer recognized by rating agencies, potentially allowing for more senior debt issuance at better terms or simply strengthening the balance sheet's resilience against volatility (like the energy price swings seen in 2022).
*   **Conclusion:** For a stable, profitable utility with low leverage, the standard corporate finance strategy is to utilize the available hybrid capacity to the fullest extent permitted by rating agency guidelines to optimize the Weighted Average Cost of Capital (WACC) and maintain rating flexibility. Therefore, they should utilize 100% of the allowed cap.

<answer>100%</answer>