To estimate the Net Debt / EBITDA ratio for ENI S.P.A. at the end of 2022 based on standard S&P methodology, we make specific adjustments to both Debt and EBITDA:

**1. S&P Adjusted Net Debt:**
S&P includes standard financial debt, capitalized lease liabilities, and unfunded pension/post-retirement obligations. S&P then deducts surplus cash and short-term liquid investments.
* Gross Debt components:
  - Short-term Borrowings: 4,446
  - Current Portion of Long-term Borrowings: 3,097
  - Long-term Borrowings: 19,374
  - Current Lease Liabilities: 884
  - Noncurrent Lease Liabilities: 4,067
  - Noncurrent Provisions For Employee Benefits (Pensions): 786
  *Total S&P Gross Debt = 32,654 million EUR*

* Cash & Liquid Investments components:
  - Cash and Cash Equivalents: 10,155
  - Current Financial Assets At Fair Value Through Profit Or Loss (marketable securities): 8,251
  - Other Current Financial Assets: 1,504
  *Total Deductions = 19,910 million EUR*

*S&P Adjusted Net Debt = 32,654 - 19,910 = 12,744 million EUR* 
*(Note: This directly aligns with ENI’s reported base net borrowings of ~€7.0B plus their ~€5.0B in lease liabilities and pensions).*

**2. S&P Adjusted EBITDA:**
S&P calculates EBITDA by taking the reported Operating Profit and adding back Depreciation & Amortization, as well as non-cash impairments and asset write-offs. 
* EBITDA components:
  - Profit (Loss) From Operating Activities: 17,510
  - Depreciation And Amortisation Expense: 7,205
  - Impairment Loss (Reversal) Recognised In Profit Or Loss: 1,140
  - Write Off Of Tangible And Intangible Assets: 599
*S&P Adjusted EBITDA = 17,510 + 7,205 + 1,140 + 599 = 26,454 million EUR*

*(Note: If one includes the €1,545M in dividends received from equity-accounted investments—a common secondary S&P adjustment—EBITDA becomes 27,999M, leading to a ratio of ~0.46x. Using the strict core operating formulation yields ~0.48x).*

**3. Net Debt / EBITDA Ratio:**
Ratio = 12,744 / 26,454 = 0.4817

<answer>0.48</answer>