Step 1 — Relevant industry

NATURGY ENERGY GROUP SA is an integrated energy group with gas/electricity networks, supply, generation, and other energy activities. Among the provided methodologies, the closest fit is Regulated Utilities / integrated power and gas utility. For the ratio calculation, I apply the baseline S&P-style corporate utility adjustments using the reported IFRS data available.

Step 2 — Estimate Adjusted EBITDA

Reported EBITDA is provided:

- Reported EBITDA = “Beneficio Bruto De Explotacion Ebitda” = €4,954 million

Lease adjustment:

- Under S&P-style adjustments, operating lease expense is typically added back to EBITDA when lease liabilities are capitalized in debt. However, the facts provide IFRS lease liabilities already on balance sheet but do not provide lease interest/depreciation or lease cash expense separately.
- Since EBITDA under IFRS 16 generally already excludes lease depreciation and interest, adding lease liabilities to debt without adding a lease expense back to EBITDA is a reasonable approximation from available data.

Nonrecurring items:

- Gains on disposals of PPE = €8 million. S&P would generally exclude nonrecurring gains from EBITDA.
- Other gains/losses = -€111 million; not enough detail to normalize, so no adjustment is made beyond the clearly identified disposal gain.

Adjusted EBITDA estimate:

- Adjusted EBITDA = €4,954m - €8m = €4,946m

Step 3 — Estimate FFO

Baseline formula:

- FFO = Adjusted EBITDA - cash interest - cash taxes

Cash interest:

- Interest paid classified as operating activities = €520 million

Cash taxes:

- Income taxes paid classified as operating activities = €762 million

Therefore:

- FFO = €4,946m - €520m - €762m
- FFO = €3,664m

Step 4 — Estimate Adjusted Debt

Reported debt components at 2023-01-01:

- Long-term borrowings = €12,689m
- Current borrowings and current portion of noncurrent borrowings = €2,110m
- Noncurrent lease liabilities = €1,309m
- Current lease liabilities = €177m

Reported debt including lease liabilities:

- Reported debt = €12,689m + €2,110m + €1,309m + €177m
- Reported debt = €16,285m

Eligible cash:

- Cash and cash equivalents = €3,985m
- In S&P adjustments, not all cash is necessarily surplus/eligible. However, no restricted cash or minimum operating cash requirement is provided. As a practical approximation, I net all cash.

Adjusted Debt:

- Adjusted Debt = €16,285m - €3,985m
- Adjusted Debt = €12,300m

Step 5 — Calculate FFO / Adjusted Debt

- FFO / Adjusted Debt = €3,664m / €12,300m
- FFO / Adjusted Debt = 0.297886...

Rounded to four decimals:

<answer>0.2979</answer>