To estimate S&P's credit trend for REN - REDES ENERGÉTICAS NACIONAIS, SGPS, S.A., we analyze the company under the "Regulated Utilities" industry methodology. We'll compute the Adjusted EBITDA, FFO, and Adjusted Debt for 2021 and 2022.

**Step 1: 2021 Estimates**
* **Adjusted EBITDA:**
Reported Operating Profit: €218.86M
Depreciation & Amortization: €241.94M
Share of Profit of Associates (to be deducted): €6.43M
Dividends Received from Investments (to be added): €13.22M
Impairment Losses (to be added back): €1.31M
*Adjusted EBITDA (2021)* = 218.86 + 241.94 - 6.43 + 13.22 + 1.31 = €468.90M

* **Funds From Operations (FFO):**
Cash Interest Paid: €39.75M (Borrowings €39.73M + Leases €0.02M)
Cash Taxes Paid: €74.25M
*FFO (2021)* = 468.90 - 39.75 - 74.25 = €354.90M

* **Adjusted Debt:**
Reported Short & Long-Term Borrowings: €2,766.07M
Pension Deficit (Noncurrent Provisions for Employee Benefits): €94.11M
Less Cash & Equivalents: €398.76M
*Adjusted Debt (2021)* = 2,766.07 + 94.11 - 398.76 = €2,461.42M

* **2021 Ratios:**
Adjusted Debt / Adjusted EBITDA = 2,461.42 / 468.90 = **5.25x**
FFO / Adjusted Debt = 354.90 / 2,461.42 = **14.42%**

**Step 2: 2022 Estimates**
* **Adjusted EBITDA:**
Reported Operating Profit: €239.72M
Depreciation & Amortization: €249.28M
Share of Profit of Associates (deducted): €11.81M
Dividends Received from Investments (added): €21.55M
Impairment Losses (added back): €1.44M
*Adjusted EBITDA (2022)* = 239.72 + 249.28 - 11.81 + 21.55 + 1.44 = €500.18M

* **Funds From Operations (FFO):**
Cash Interest Paid: €40.57M (Borrowings €40.54M + Leases €0.03M)
Cash Taxes Paid: €77.97M
*FFO (2022)* = 500.18 - 40.57 - 77.97 = €381.64M

* **Adjusted Debt:**
Reported Short & Long-Term Borrowings: €2,334.31M
Pension Deficit: €64.94M
Less Cash & Equivalents: €365.29M
*Adjusted Debt (2022)* = 2,334.31 + 64.94 - 365.29 = €2,033.96M

* **2022 Ratios:**
Adjusted Debt / Adjusted EBITDA = 2,033.96 / 500.18 = **4.07x**
FFO / Adjusted Debt = 381.64 / 2,033.96 = **18.76%**

**Step 3: Credit Trend Evaluation**
* **Signal 1 (Leverage):** The Adjusted Debt / Adjusted EBITDA ratio decreased from 5.25x to 4.07x, a substantial change of -1.18x. Since this is well below the -0.2x threshold, this indicates an *Improving* trend.
* **Signal 2 (Cash-flow coverage):** The FFO / Adjusted Debt ratio increased from 14.42% to 18.76%, a change of +4.34 percentage points (+0.0434). Since this clears the +0.03 threshold, this also indicates an *Improving* trend.

With strong deleveraging through strong free operating cash flow generation leading to debt paydown, both indicators cleanly point to a positive trajectory.

<answer>Improving</answer>