To estimate the Net Debt / EBITDA ratio for Italgas S.p.A. for the year 2022 (period ending 2023-01-01) using the S&P methodology, we need to calculate two components: Adjusted EBITDA and Net Debt.

**1. Calculate Adjusted EBITDA**

S&P typically defines EBITDA as Earnings Before Interest, Taxes, Depreciation, and Amortization. We can derive this from the provided Income Statement data for the period 2022-01-01 to 2023-01-01.

*   **Profit Loss From Operating Activities (EBIT):** 641,338,000 EUR
*   **Depreciation, Amortisation, and Impairment:** 479,186,000 EUR
    *   *Note: The line item "Depreciation Amortisation And Impairment Loss Reversal Of Impairment Loss Recognised In Profit Or Loss" is the standard add-back for EBITDA.*

**EBITDA Calculation:**
$$EBITDA = \text{Operating Profit} + \text{Depreciation \& Amortization}$$
$$EBITDA = 641,338,000 + 479,186,000 = 1,120,524,000 \text{ EUR}$$

*Self-Correction/Refinement:* Sometimes "Other Revenue and Income" or specific adjustments are considered, but standard EBITDA from operating profit is the most robust base. S&P often uses "Funds From Operations" (FFO) or adjusted metrics, but for a standard Net Debt/EBITDA ratio, this is the denominator. Let's verify if there are significant non-operating items. The "Profit Loss Before Tax" is 588,495,000. Adding back Finance Costs (61,367,000) and subtracting Finance Income (4,043,000) roughly gets us back to operating profit levels. The standard EBITDA definition holds.

**EBITDA = 1,120,524,000 EUR**

**2. Calculate Net Debt**

S&P defines Net Debt as Total Debt minus Cash and Cash Equivalents. Total Debt usually includes short-term and long-term interest-bearing liabilities.

**A. Identify Interest-Bearing Debt (Gross Debt)**

From the Balance Sheet data as of 2023-01-01 (end of 2022):

*   **Short Term Financial Liabilities:**
    *   "Short Term Financial Liabilities Excluding Other Current Financial Liabilities": 142,437,000 EUR
    *   "Other Current Financial Liabilities": 290,000 EUR
    *   *Total Short-Term Debt* = $142,437,000 + 290,000 = 142,727,000$ EUR

*   **Long Term Financial Liabilities:**
    *   "Long Term Financial Liabilities Excluding Other Non Current Financial Liabilities": 6,402,913,000 EUR
    *   "Other Noncurrent Financial Liabilities": 34,000 EUR
    *   *Total Long-Term Debt* = $6,402,913,000 + 34,000 = 6,402,947,000$ EUR

*   **Total Gross Debt** = $142,727,000 + 6,402,947,000 = 6,545,674,000$ EUR

*Note: We exclude "Trade And Other Current Payables", "Provisions", "Tax Liabilities", and "Other Nonfinancial Liabilities" as these are operational liabilities, not financial debt.*

**B. Identify Cash and Cash Equivalents**

*   "Cash And Cash Equivalents" 2023-01-01: 451,946,000 EUR

*Note: S&P may sometimes include "Current Financial Assets" if they are highly liquid and held for cash management purposes. Let's check "Current Financial Assets Excluding Other Current Financial Assets" (5,770,000 EUR) and "Other Current Financial Assets" (17,455,000 EUR). However, standard Net Debt calculations primarily subtract Cash & Cash Equivalents. Even if we included short-term financial assets, the impact is minimal (< 25M EUR). We will stick to the strict Cash & Cash Equivalents for the primary calculation, as is common unless "Cash and short-term investments" is specified.*

**C. Calculate Net Debt**

$$Net Debt = \text{Total Gross Debt} - \text{Cash and Cash Equivalents}$$
$$Net Debt = 6,545,674,000 - 451,946,000 = 6,093,728,000 \text{ EUR}$$

**3. Calculate Net Debt / EBITDA Ratio**

$$Ratio = \frac{\text{Net Debt}}{\text{EBITDA}}$$
$$Ratio = \frac{6,093,728,000}{1,120,524,000}$$

$$Ratio \approx 5.438$$

Let's double-check the components.
*   **EBITDA**: 1,120.5 million EUR.
*   **Net Debt**: 6,093.7 million EUR.

Calculation: $6093.728 / 1120.524 = 5.43828...$

Rounding to two decimal places, the ratio is 5.44.

<answer>5.44</answer>