To estimate S&P's credit trend for TenneT Holding B.V. from 2021 to 2022, we apply the Regulated Utilities methodology. TenneT operates as a transmission system operator, heavily regulated, but under IFRS it cannot always capitalize regulatory deferral accounts. This means soaring energy prices in 2022 directly impacted its reported IFRS operating costs (grid losses and redispatching) prior to their future recovery through tariffs, skewing reported profitability. 

**Step 1: 2021 Adjusted EBITDA**
* Reported Profit/Loss from Operating Activities: -€275m
* Add back D&A: +€1,165m
* Less: Share of Profit of JV/Associates: -€62m
* Add: Dividends received from JV/Associates: +€56m
* Add: Non-recurring losses (Other Gains/Losses): +€4m
* **2021 Adjusted EBITDA** ≈ €888m

**Step 2: 2021 FFO**
* Cash Interest Paid: -€174m 
* Interest Received: +€3m
* Hybrid Capital Dividends (50% treated as interest): -€28.5m
* Cash Taxes Paid: -€246m
* **2021 FFO** = €888m - €174m + €3m - €28.5m - €246m ≈ €442.5m

**Step 3: 2021 Adjusted Debt**
* Long-term Borrowings: €12,366m
* Short-term Borrowings: €1,339m
* Bank Overdrafts: €64m
* Lease Liabilities (Current & Noncurrent): €404m
* Hybrid Capital (50% debt treatment): €1,062.5m
* Pension Liabilities: €351m
* Less: Eligible Cash & Equivalents: -€3,204m
* **2021 Adjusted Debt** ≈ €12,382.5m

**2021 Ratios**
* **Adjusted Debt / Adjusted EBITDA** = 12,382.5 / 888 ≈ **13.9x**
* **FFO / Adjusted Debt** = 442.5 / 12,382.5 ≈ **3.6%**

**Step 4: 2022 Adjusted EBITDA**
* Reported Profit/Loss from Operating Activities: -€976m
* Add back D&A: +€1,233m
* Less: Share of Profit of JV/Associates: -€120m
* Add: Dividends received from JV/Associates: +€92m
* Add: Non-recurring losses (Other Gains/Losses): +€38m
* **2022 Adjusted EBITDA** ≈ €267m

**Step 5: 2022 FFO**
* Cash Interest Paid: -€202m 
* Interest Received: +€45m
* Hybrid Capital Dividends (50% treated as interest): -€28.5m
* Cash Taxes Paid: -€231m
* **2022 FFO** = €267m - €202m + €45m - €28.5m - €231m ≈ -€149.5m

**Step 6: 2022 Adjusted Debt**
* Long-term Borrowings: €19,006m
* Short-term Borrowings: €709m
* Lease Liabilities (Current & Noncurrent): €729m
* Hybrid Capital (50% debt treatment): €1,062.5m
* Pension Liabilities: €174m
* Less: Eligible Cash & Equivalents: -€6,547m
* **2022 Adjusted Debt** ≈ €15,133.5m

**2022 Ratios**
* **Adjusted Debt / Adjusted EBITDA** = 15,133.5 / 267 ≈ **56.7x**
* **FFO / Adjusted Debt** = -149.5 / 15,133.5 ≈ **-1.0%**

**Step 7: Trend Classification**
* **Signal 1 (Leverage):** 56.7x - 13.9x = +42.8x (≥ +0.2x, indicating Deteriorating)
* **Signal 2 (Cash-flow coverage):** -0.010 - 0.036 = -0.046 (≤ -0.03, indicating Deteriorating)

Due to the massive surge in "Energy Transmission Charges" outstripping immediate revenue during the 2022 European energy crisis, profitability and operating cash flow metrics nosedived under IFRS, and the need to pre-finance this under-recovery vastly inflated debt. Both signals unequivocally point to a substantial weakening in near-term credit metrics. 

<answer>Deteriorating</answer>