Net Debt is estimated as financial debt minus cash and cash equivalents.

For 2022 balance sheet date:
- Financial debt = Other noncurrent financial liabilities + Other current financial liabilities  
= 4,322m + 746m = 5,068m
- Cash and cash equivalents = 964m
- Net Debt = 5,068m − 964m = 4,104m
- EBITDA for 2021 period = 1,428m
- Net Debt / EBITDA = 4,104 / 1,428 = 2.87x

For 2023 balance sheet date:
- Financial debt = Other noncurrent financial liabilities + Other current financial liabilities  
= 5,867m + 1,022m = 6,889m
- Cash and cash equivalents = 2,584m
- Net Debt = 6,889m − 2,584m = 4,305m
- EBITDA for 2022 period = 1,505m
- Net Debt / EBITDA = 4,305 / 1,505 = 2.86x

Year-on-year change:
- 2.86x − 2.87x = -0.01x

The leverage ratio decreased slightly, and the change is within ±0.3x. Under the stated definition, this indicates a stable trend.

<answer>Stable</answer>