## Reasoning

### Step 1: Calculate EBITDA (S&P methodology)

S&P's EBITDA typically starts with operating profit and adds back depreciation and amortization. However, S&P also makes various adjustments. Let me work with what's available.

From the data, for the period 2022-01-01 to 2023-01-01 (fiscal year 2022):

**Operating Profit Before Depreciation and Amortisation (EBE/EBITDA):** -4,986,000,000 EUR

This is essentially the company's reported EBITDA figure. However, S&P's EBITDA methodology typically uses:

EBITDA = Revenue - Operating Expenses + D&A (added back) or equivalently, Operating Profit + D&A

Let me verify using the reported figures:
- Profit Loss From Operating Activities: -19,363,000,000
- Add back D&A: 11,079,000,000
- Add back Impairment: 1,762,000,000
- This gives: -19,363 + 11,079 + 1,762 = -6,522 million

But the company reports "Operating Profit Before Depreciation And Amortisation" = -4,986 million, which is their EBE (Excédent Brut d'Exploitation).

The difference between -4,986 and the operating profit + D&A relates to other items excluded from EBE:
- Net Changes In Fair Value on Energy and Commodity Derivatives: -849
- Impairment: -1,762
- Other Income and Expenses Excluded from EBE: +687

So: -4,986 - 849 - 1,762 + 687 = -6,910... Let me recalculate:
Operating Profit = EBE - Fair Value changes - D&A - Impairment + Other excluded items
-19,363 = -4,986 + (-849) - 11,079 - 1,762 + (-687)
-4,986 - 849 - 11,079 - 1,762 - 687 = -19,363 ✓

For S&P EBITDA, we typically use:
EBITDA = Operating Profit + D&A + Impairment (sometimes)

S&P's adjusted EBITDA would typically:
- Start with reported EBITDA (EBE) = -4,986 million
- But S&P includes operating lease adjustments and other items

For simplicity and given available data, let me use the reported EBITDA (EBE) = -4,986 million EUR as a proxy. However, S&P might also add back impairments. Let me consider EBITDA as the operating profit before D&A figure: **-4,986 million EUR**.

### Step 2: Calculate Net Debt (S&P methodology)

S&P Net Debt = Total Debt - Cash and Cash Equivalents - Short-term investments

From the balance sheet at 2023-01-01 (end of fiscal year 2022):

**Debt components:**
- Other Noncurrent Financial Liabilities: 71,058,000,000
- Other Current Financial Liabilities: 71,844,000,000

But these include derivatives and other items. S&P typically considers:
- Gross financial debt (bonds, loans, etc.)

However, the current financial liabilities likely include significant derivative positions and margin calls given the energy crisis. Let me try a more conservative approach.

A simpler approach: S&P often looks at reported net financial debt. EDF typically reports this.

Let me estimate:
- Noncurrent financial liabilities: 71,058 million
- Current financial liabilities: 71,844 million
- Less: Cash: 10,948 million
- Less: Current financial assets: 58,033 million
- Less: Noncurrent financial assets: 48,512 million (but this includes dedicated assets for nuclear provisions)

This gets complicated. Let me use a more standard approach:

Gross Debt = Noncurrent financial liabilities + Current financial liabilities = 71,058 + 71,844 = 142,902 million

But much of the current financial liabilities are derivative positions (margin calls, etc.), not traditional debt.

EDF's reported net financial debt for 2022 was approximately 64.5 billion EUR. Given S&P methodology adjustments (adding operating lease obligations, pension obligations as debt-like, 50% of hybrid instruments), S&P adjusted debt would be higher.

Let me approximate using available data:
- Gross debt ≈ 71,058 (noncurrent) + portion of current financial liabilities
- Cash: 10,948 million

A reasonable estimate for EDF's net debt per S&P: approximately 64-65 billion EUR for the basic net debt, but S&P adds hybrids and pension adjustments.

Given the EBITDA is negative (-4,986 million), the ratio would be negative, which isn't particularly meaningful. But let me compute it.

Using approximate net financial debt of ~64,500 million and EBITDA of -4,986 million:

Net Debt / EBITDA = 64,500 / (-4,986) ≈ -12.9

This is a negative ratio due to negative EBITDA, which S&P would flag as not meaningful. But the question asks to estimate it.

Let me reconsider - EDF's reported net financial debt at end 2022 was about 64.5 billion EUR.

Net Debt / EBITDA = 64,500 / (-4,986) ≈ -12.93

<answer>-12.9</answer>