To estimate the S&P-adjusted debt-to-EBITDA ratio for Italgas S.p.A. for the fiscal year 2022, we follow the prescribed workflow.

### 1. Identify Industry
Italgas S.p.A. is a regulated gas distribution utility. It falls under the **"Regulated Utilities"** methodology.

### 2. Estimate Adjusted_Debt
*   **Reported Debt (2022-12-31/2023-01-01):**
    *   Short-term financial liabilities: 142,437,000 EUR
    *   Long-term financial liabilities: 6,402,913,000 EUR
    *   Other current financial liabilities: 290,000 EUR
    *   Other non-current financial liabilities: 34,000 EUR
    *   Total Reported Debt = 142,437,000 + 6,402,913,000 + 290,000 + 34,000 = **6,545,674,000 EUR**
*   **Pension Deficit:** Noncurrent Provisions for Employee Benefits = **69,917,000 EUR**
*   **Eligible Cash:** Cash and Cash Equivalents = **451,946,000 EUR**
*   **Adjusted_Debt Calculation:**
    *   Adjusted_Debt = Reported Debt + Pension Deficit - Eligible Cash
    *   Adjusted_Debt = 6,545,674,000 + 69,917,000 - 451,946,000 = **6,163,645,000 EUR**

### 3. Estimate Adjusted_EBITDA
*   **Reported EBITDA Calculation:**
    *   Operating Profit: 641,338,000 EUR
    *   Add: Depreciation, Amortization, and Impairment: 479,186,000 EUR
    *   Reported EBITDA = 641,338,000 + 479,186,000 = **1,120,524,000 EUR**
*   **Adjustments:**
    *   The methodology indicates we should account for leasing. However, "Cash Outflow For Leases" (27,865,000 EUR) is provided. In S&P adjustments for regulated utilities, depreciation on leases is often already included in reported figures, and interest is handled via finance costs. We maintain the operating EBITDA as the primary figure.
    *   Other non-recurring adjustments (e.g., disposal gains/losses): 25,357,000 EUR (Gains on disposal of noncurrent assets). This is a non-recurring gain that should be subtracted.
    *   Adjusted_EBITDA = 1,120,524,000 - 25,357,000 = **1,095,167,000 EUR**

### 4. Calculate Ratio
*   Ratio = Adjusted_Debt / Adjusted_EBITDA
*   Ratio = 6,163,645,000 / 1,095,167,000 ≈ 5.6276

Rounding to two decimal places: 5.63.

<answer>5.63</answer>