To calculate the Net Debt / EBITDA ratio for ERG S.p.A. for the year 2022 (ending 2023-01-01), we follow the standard financial methodology using the provided data.

**1. EBITDA Calculation:**
The report explicitly provides the "Profit Loss From Operating Activities Before Interest Taxes Depreciation And Amortisation Expense" for 2022:
EBITDA = 499,430,000 EUR.

**2. Net Debt Calculation:**
Net Debt is generally defined as total financial debt (current and non-current financial liabilities) minus cash and cash equivalents.
*   **Current Financial Liabilities:**
    *   Current Financial Liabilities At Fair Value Through Profit Or Loss: 76,644,000 EUR
    *   Other Current Financial Liabilities: 389,716,000 EUR
    *   Current Lease Liabilities: 6,362,000 EUR
    *   *Total Current Financial Liabilities* = 472,722,000 EUR
*   **Non-Current Financial Liabilities:**
    *   Noncurrent Financial Liabilities At Fair Value Through Profit Or Loss: 0 EUR
    *   Other Noncurrent Financial Liabilities: 1,751,255,000 EUR
    *   Noncurrent Lease Liabilities: 150,955,000 EUR
    *   *Total Non-Current Financial Liabilities* = 1,902,210,000 EUR
*   **Total Financial Debt** = 472,722,000 + 1,902,210,000 = 2,374,932,000 EUR
*   **Cash and Cash Equivalents** = 392,811,000 EUR
*   **Net Debt** = Total Debt - Cash = 2,374,932,000 - 392,811,000 = 1,982,121,000 EUR

**3. Ratio Calculation:**
Net Debt / EBITDA = 1,982,121,000 / 499,430,000 ≈ 3.9687...

Rounding to two decimal places, we get 3.97.

<answer>3.97</answer>