I need to estimate S&P's adjusted leverage (Net Debt / EBITDA) for both years and compare them.

## Step 1: Calculate Net Debt

**Net Debt = Financial Debt - Cash and Cash Equivalents**

Financial Debt includes noncurrent and current financial liabilities, lease liabilities, and concession liabilities, minus cash.

For **2022-01-01** (end of 2021/start of 2022):
- Noncurrent Financial Liabilities excl. concession: 10,462.5M
- Current Financial Liabilities excl. concession: 8,624.3M
- Noncurrent Lease Liabilities: 1,298.1M
- Current Lease Liabilities: 410.6M
- Noncurrent Concession Liabilities: 1,588.4M
- Current Concession Liabilities: 169.4M
- Bank Overdrafts: 241.9M
- Total Gross Debt: 22,795.2M
- Cash: 10,518.7M
- **Net Debt ≈ 12,276.5M**

For **2023-01-01** (end of 2022/start of 2023):
- Noncurrent Financial Liabilities excl. concession: 19,692.1M
- Current Financial Liabilities excl. concession: 6,521.4M
- Noncurrent Lease Liabilities: 1,656.2M
- Current Lease Liabilities: 496.5M
- Noncurrent Concession Liabilities: 1,680.5M
- Current Concession Liabilities: 243.2M
- Bank Overdrafts: 213.6M
- Total Gross Debt: 30,503.5M
- Cash: 9,012.2M
- **Net Debt ≈ 21,491.3M**

## Step 2: Calculate EBITDA

**EBITDA ≈ Operating Income + Depreciation/Amortization**

For **2021-01-01 to 2022-01-01** (FY2021):
- Operating Income (before equity method): 1,212.7M
- Operating D&A: 2,117.2M
- **EBITDA ≈ 3,329.9M**

For **2022-01-01 to 2023-01-01** (FY2022):
- Operating Income (before equity method): 2,206.3M
- Operating D&A: 3,178.6M
- **EBITDA ≈ 5,384.9M**

## Step 3: Calculate Net Debt / EBITDA

For the leverage ratio, I should use end-of-period debt with the period's EBITDA.

**FY2021 leverage**: Net Debt (end 2021) / EBITDA (2021) = 12,276.5 / 3,329.9 ≈ **3.69x**

**FY2022 leverage**: Net Debt (end 2022) / EBITDA (2022) = 21,491.3 / 5,384.9 ≈ **3.99x**

## Step 4: Assess the trend

The change in leverage: 3.99x - 3.69x = +0.30x

This is right at the boundary. The question states that stable is "among ± 0.3x" year on year. The increase of 0.30x is at the threshold. However, S&P typically would exclude lease liabilities and concession liabilities from their adjusted debt calculation in some frameworks, or include operating leases differently.

Let me recalculate excluding concession and lease liabilities (using only core financial debt):

**FY2021 Net Debt**: (10,462.5 + 8,624.3 + 241.9) - 10,518.7 = 8,810.0M
**FY2022 Net Debt**: (19,692.1 + 6,521.4 + 213.6) - 9,012.2 = 17,414.9M

FY2021: 8,810 / 3,329.9 = 2.65x
FY2022: 17,414.9 / 5,384.9 = 3.23x

Change: +0.58x → Deteriorating

The massive increase in debt from the Suez acquisition drove leverage higher. Even with EBITDA growing significantly from the Suez consolidation, the debt increase was proportionally larger.

The gap is clearly greater than 0.3x, pointing to **Deteriorating**.

<answer>Deteriorating</answer>