### Step 1: Industry Identification
"REDEIA CORPORACION SA" (formerly Red Eléctrica Corporación, S.A.) is the Spanish national electricity transmission grid operator. This falls under **Regulated Utilities**.

### Step 2 & 7: Adjusted EBITDA Calculation
Formula: Profit from Operating Activities + Depreciation & Amortisation Expense.
*   **2021:** 991,970,000 + 522,114,000 = **1,514,084,000 EUR**
*   **2022:** 961,554,000 + 544,992,000 = **1,506,546,000 EUR**

### Step 3 & 8: FFO Calculation
Formula: Adjusted_EBITDA - Interest Paid (Operating) - Income Taxes Paid.
*   **2021:** 1,514,084,000 - 121,920,000 - 181,263,000 = **1,210,901,000 EUR**
*   **2022:** 1,506,546,000 - 123,524,000 - 363,996,000 = **1,019,026,000 EUR**

### Step 4 & 9: Adjusted Debt Calculation
Formula: Longterm Borrowings + Current Borrowings - Cash & Cash Equivalents.
*   **2021 (Reported 2022-01-01):** 5,896,170,000 + 1,391,722,000 - 1,574,427,000 = **5,713,465,000 EUR**
*   **2022 (Reported 2023-01-01):** 5,491,124,000 + 721,845,000 - 794,824,000 = **5,418,145,000 EUR**

### Step 5 & 10: Adjusted Debt / Adjusted EBITDA
*   **2021:** 5,713,465,000 / 1,514,084,000 = **3.77x**
*   **2022:** 5,418,145,000 / 1,506,546,000 = **3.60x**
*   **Signal 1 Change:** 3.60 - 3.77 = **-0.17x (Stable)**

### Step 6 & 11: FFO / Adjusted Debt
*   **2021:** 1,210,901,000 / 5,713,465,000 = **0.212**
*   **2022:** 1,019,026,000 / 5,418,145,000 = **0.188**
*   **Signal 2 Change:** 0.188 - 0.212 = **-0.024 (Stable)**

### Step 12: Classification
*   Signal 1 (Leverage): -0.17x (Stable)
*   Signal 2 (Coverage): -0.024 (Stable)

Both signals are within the defined thresholds for "Stable". Therefore, the credit trend is classified as Stable.

<answer>Stable</answer>