I'll work through this step-by-step, analyzing REDEIA CORPORACION SA's financial data to estimate S&P's credit trend from 2021 to 2022.

## Step 1: Identify the Relevant Industry

REDEIA CORPORACION SA (Red Eléctrica Corporación) is Spain's national electricity transmission grid operator (TSO). This is a **regulated utility** - specifically an electricity transmission company operating under regulated tariffs with natural monopoly characteristics. The company operates under Spain's regulatory framework for electricity transmission.

## Step 2: Estimate 2021 Adjusted_EBITDA

First, I need to reconstruct EBITDA for 2021. For regulated utilities, S&P focuses on actual cash flow generation and economics.

From the income statement for 2021 (period 2021-01-01 to 2022-01-01):
- Revenue: 1,952,958,000 EUR
- Employee Benefits Expense: 187,341,000 EUR
- Miscellaneous Other Operating Expense: 344,252,000 EUR
- Depreciation And Amortisation Expense: 522,114,000 EUR
- Profit Loss From Operating Activities (EBIT): 991,970,000 EUR

EBITDA = EBIT + Depreciation and Amortization = 991,970,000 + 522,114,000 = **1,514,084,000 EUR**

For regulated utilities, S&P notes they don't adjust for regulatory accounting effects. Let me check for adjustments needed:
- No lease adjustments mentioned in data
- No nonrecurring items clearly identified
- No pension adjustments visible
- Joint venture: "Participacion En Beneficios De Sociedades Valoradas Por El Metodo De La Participacion" = 29,546,000 EUR (equity method income, already in EBIT)

For regulated utilities, S&P may add back certain items. Looking at the structure, this is a transmission company with largely fixed-cost recovery.

Adjusted_EBITDA_2021 ≈ **1,514,084,000 EUR** (using reported EBITDA as base, minimal adjustments needed for regulated transmission)

Actually, let me recalculate more carefully. For S&P purposes, I'll use:
- EBITDA = Revenue - Operating Expenses (excluding D&A) = 1,952,958,000 - 187,341,000 - 344,252,000 + 29,546,000 (equity method) + 10,644,000 (misc income) + 55,737,000 (capitalized work) - 18,655,000 (aprovisionamientos) + 14,717,000 (subsidies) - (-730,000) (asset disposals) = ?

Let me use simpler approach: EBIT + D&A = 991,970,000 + 522,114,000 = 1,514,084,000 EUR

Add equity method income (already in EBIT, so not additive). 

For regulated utilities, S&P uses EBITDA margin or ROC. The equity method income is already included in operating profit.

Adjusted_EBITDA_2021 = **1,514,084,000 EUR**

## Step 3: Estimate 2021 FFO

FFO = Adjusted_EBITDA - cash_interest - cash_taxes

From cash flow statement 2021:
- Interest Paid (operating activities): 121,920,000 EUR
- Income Taxes Paid: 181,263,000 EUR

FFO_2021 = 1,514,084,000 - 121,920,000 - 181,263,000 = **1,210,901,000 EUR**

Alternatively, using cash flow from operations: 1,605,176,000 EUR. But S&P defines FFO as EBITDA - cash interest - cash taxes.

Let me verify with operating cash flow approach: FFO should approximate CFO before working capital changes.
- Profit: 686,284,000
- D&A: 522,114,000
- Other adjustments: 584,630,000 (includes equity income, finance costs, etc.)
= 1,793,028,000 before working capital and interest/tax adjustments

Actually, S&P's FFO formula is: Adjusted_EBITDA - cash interest - cash taxes

Using: 1,514,084,000 - 121,920,000 - 181,263,000 = **1,210,901,000 EUR**

## Step 4: Estimate 2021 Adjusted_Debt

Adjusted_Debt = reported_debt + leases + pension_deficit + guarantees + hybrid_debt_portion + other_debt_like_items - eligible_cash

From balance sheet 2022-01-01 (beginning of 2022 = end of 2021):
- Noncurrent Financial Liabilities: 5,953,434,000 EUR
  - Longterm Borrowings: 5,896,170,000 EUR
  - Other Noncurrent Financial Liabilities: 57,264,000 EUR
- Current Financial Liabilities: 2,144,425,000 EUR
  - Current Borrowings: 1,391,722,000 EUR
  - Other Current Financial Liabilities: 752,703,000 EUR

Total reported debt = 5,953,434,000 + 2,144,425,000 = 8,097,859,000 EUR

For regulated utilities, S&P notes:
- No lease adjustments mentioned (no lease liabilities visible in data)
- No pension deficit visible
- No guarantees identified
- No hybrid debt mentioned

Eligible cash: Cash and Cash Equivalents = 1,574,427,000 EUR

However, S&P typically uses a portion of cash. For conservative estimate, let's use 100% or apply standard practice. S&P often uses "surplus cash" but for simplicity, I'll deduct full cash or apply a standard approach.

Actually, looking more carefully: S&P deducts "eligible cash" - typically cash not required for operations. For regulated utilities with working capital needs, not all cash is eligible.

Adjusted_Debt_2021 = 8,097,859,000 - 0 (no clear lease/pension adjustments) - eligible_cash

Using reported debt less cash for conservative estimate: 8,097,859,000 - 1,574,427,000 = **6,523,432,000 EUR** (assuming all cash is eligible, which is optimistic)

Or with no cash deduction (more conservative for credit analysis): 8,097,859,000 EUR

Let me use a balanced approach - typically S&P might consider 1/3 to 1/2 of cash as truly excess. But without specific guidance, I'll use full debt and note the cash position.

Actually, re-reading S&P methodology: "eligible_cash" - they typically deduct cash and equivalents that are truly available to repay debt.

For conservative credit analysis, let me use: Adjusted_Debt = 8,097,859,000 - 1,574,427,000 = **6,523,432,000 EUR**

Wait - I need to check if there are derivative positions. The company has derivative assets and liabilities. S&P may include derivative liabilities or net them.

Noncurrent Derivative Financial Liabilities: 16,436,000
Current Derivative Financial Liabilities: 5,129,000
Total derivative liabilities: 21,565,000

Derivative assets: 23,592,000 + 91,000 = 23,683,000

Net derivative liability: not material enough to adjust significantly.

Adjusted_Debt_2021 ≈ **6,500,000,000 EUR** (rounded, or more precisely 6,523,432,000)

## Step 5: Calculate 2021 Adjusted_Debt / Adjusted_EBITDA

6,523,432,000 / 1,514,084,000 = **4.31x**

Or if using gross debt: 8,097,859,000 / 1,514,084,000 = 5.35x

## Step 6: Calculate 2021 FFO / Adjusted_Debt

1,210,901,000 / 6,523,432,000 = **0.186** or 18.6%

## Step 7: Estimate 2022 Adjusted_EBITDA

From 2022 income statement (2022-01-01 to 2023-01-01):
- Revenue: 2,015,036,000 EUR
- Employee Benefits Expense: 210,614,000 EUR
- Miscellaneous Other Operating Expense: 467,088,000 EUR
- Depreciation And Amortisation Expense: 544,992,000 EUR
- Profit Loss From Operating Activities (EBIT): 961,554,000 EUR

EBITDA = 961,554,000 + 544,992,000 = **1,506,546,000 EUR**

Adjusted_EBITDA_2022 = **1,506,546,000 EUR**

## Step 8: Estimate 2022 FFO

From cash flow statement 2022:
- Interest Paid: 123,524,000 EUR
- Income Taxes Paid: 363,996,000 EUR

FFO_2022 = 1,506,546,000 - 123,524,000 - 363,996,000 = **1,019,026,000 EUR**

## Step 9: Estimate 2022 Adjusted_Debt

From balance sheet 2023-01-01 (end of 2022):
- Noncurrent Financial Liabilities: 5,543,755,000 EUR
  - Longterm Borrowings: 5,491,124,000 EUR
  - Other Noncurrent Financial Liabilities: 52,631,000 EUR
- Current Financial Liabilities: 1,705,277,000 EUR
  - Current Borrowings: 721,845,000 EUR
  - Other Current Financial Liabilities: 983,432,000 EUR

Total reported debt = 5,543,755,000 + 1,705,277,000 = 7,249,032,000 EUR

Cash and Cash Equivalents: 794,824,000 EUR

Adjusted_Debt_2022 = 7,249,032,000 - 794,824,000 = **6,454,208,000 EUR**

## Step 10: Calculate 2022 Adjusted_Debt / Adjusted_EBITDA

6,454,208,000 / 1,506,546,000 = **4.28x**

## Step 11: Calculate 2022 FFO / Adjusted_Debt

1,019,026,000 / 6,454,208,000 = **0.158** or 15.8%

## Step 12: Classify Year-on-Year Credit Trend

**Signal 1: Leverage (Adjusted_Debt / Adjusted_EBITDA)**
- 2021: 4.31x
- 2022: 4.28x
- Change: 4.28 - 4.31 = **-0.03x**

Threshold: ≤ -0.2x for Improving, ≥ +0.2x for Deteriorating
-0.03x is between -0.2x and +0.2x → **Stable**

**Signal 2: Cash-flow coverage (FFO / Adjusted_Debt)**
- 2021: 0.186
- 2022: 0.158
- Change: 0.158 - 0.186 = **-0.028** or -2.8 percentage points

Threshold: ≥ +0.03 for Improving, ≤ -0.03 for Deteriorating
-0.028 is between -0.03 and +0.03 → **Stable** (barely, very close to Deteriorating threshold)

Wait, let me recheck: -0.028 is greater than -0.03, so it's in the Stable range (between -0.03 and +0.03).

Actually -0.028 > -0.03, so it's Stable. But very close to the Deteriorating boundary.

Let me recalculate more precisely:

FFO_2021 = 1,514,084,000 - 121,920,000 - 181,263,000 = 1,210,901,000
FFO/Debt_2021 = 1,210,901,000 / 6,523,432,000 = 0.1856

FFO_2022 = 1,506,546,000 - 123,524,000 - 363,996,000 = 1,019,026,000
FFO/Debt_2022 = 1,019,026,000 / 6,454,208,000 = 0.1579

Change = 0.1579 - 0.1856 = **-0.0277** or approximately **-0.028**

This is -2.77 percentage points, which is > -0.03, so **Stable**.

But let me reconsider: is -0.0277 really Stable? The threshold is ≤ -0.03 for Deteriorating. Since -0.0277 > -0.03, it's Stable.

However, I want to double-check my EBITDA and debt calculations, as these are critical.

**Rechecking 2021:**
- Revenue: 1,952,958,000
- Less: Employee benefits 187,341,000
- Less: Other operating expenses 344,252,000
- Less: Aprovisionamientos 18,655,000
- Plus: Other work capitalized 55,737,000
- Plus: Equity method income 29,546,000
- Plus: Misc other operating income 10,644,000
- Plus: Subsidies 14,717,000
- Plus: Asset disposals gain -730,000 (negative, so loss)
= EBIT before D&A: 1,952,958 - 187,341 - 344,252 - 18,655 + 55,737 + 29,546 + 10,644 + 14,717 + 730 = 1,514,084,000? 

Wait, let me verify: 1,952,958 - 187,341 = 1,765,617; - 344,252 = 1,421,365; - 18,655 = 1,402,710; + 55,737 = 1,458,447; + 29,546 = 1,487,993; + 10,644 = 1,498,637; + 14,717 = 1,513,354; + 730 = 1,514,084. Yes matches.

Then EBIT = 1,514,084 - 522,114 (D&A) = 991,970. ✓

**Rechecking 2022:**
Revenue 2,015,036 - 210,614 - 467,088 - 37,061 + 62,903 + 50,405 + 77,673 + 15,780 + 488 = 1,506,546? 

2,015,036 - 210,614 = 1,804,422; - 467,088 = 1,337,334; - 37,061 = 1,300,273; + 62,903 = 1,363,176; + 50,405 = 1,413,581; + 77,673 = 1,491,254; + 15,780 = 1,507,034; + 488 = 1,507,522? 

Hmm, that doesn't match. Let me recheck: "Deterioro YResultado Por Enajenaciones Del Inmovilizado" = 488,000 (positive, gain). 

Actually my manual calc gives 1,507,522 vs reported EBIT+D&A = 961,554 + 544,992 = 1,506,546. Difference of ~1M, likely rounding or I misread something.

Let me use the reported EBIT + D&A = 1,506,546,000 as more reliable.

**Debt recheck:**

For 2021 (using 2022-01-01 balance sheet):
- Noncurrent Financial Liabilities: 5,953,434,000
- Current Financial Liabilities: 2,144,425,000
Total: 8,097,859,000

For 2022 (using 2023-01-01 balance sheet):
- Noncurrent Financial Liabilities: 5,543,755,000
- Current Financial Liabilities: 1,705,277,000
Total: 7,249,032,000

Debt decreased by 848,827,000. Cash decreased from 1,574,427,000 to 794,824,000 = 779,603,000.

Net debt: 2021: 8,097,859 - 1,574,427 = 6,523,432; 2022: 7,249,032 - 794,824 = 6,454,208.

Net debt decreased by 69,224,000.

**Signal 1: Leverage change**
2021: 6,523,432 / 1,514,084 = 4.308x
2022: 6,454,208 / 1,506,546 = 4.284x
Change: -0.024x → **Stable**

**Signal 2: FFO/Debt change**
2021: 1,210,901 / 6,523,432 = 0.1856
2022: 1,019,026 / 6,454,208 = 0.1579
Change: -0.0277 → **Stable** (just above -0.03 threshold)

Both signals are Stable.

However, I want to reconsider if my FFO calculation is correct. S&P's FFO is typically:
FFO = Funds from operations = Net income + D&A + deferred taxes + other non-cash items - working capital changes? 

No, for S&P credit analysis, FFO is typically:
FFO = EBITDA - cash interest - cash taxes (as I used)

Or sometimes: FFO = Net income + D&A + deferred taxes - equity earnings + other non-cash items

Let me try alternative FFO calculation:
2021: Net income 686,284 + D&A 522,114 + deferred tax change (70,567 - ?) ... 

Actually the S&P formula I was given is: FFO = Adjusted_EBITDA - cash_interest - cash_taxes

This is clear. Let me verify cash interest and taxes from cash flow statement.

From 2021 cash flows:
- Interest Paid: 121,920,000
- Income Taxes Paid: 181,263,000

From 2022 cash flows:
- Interest Paid: 123,524,000
- Income Taxes Paid: 363,996,000

These are correct.

One concern: 2022 taxes paid jumped significantly from 181M to 364M, nearly doubling. This affects FFO materially. Is this a one-time item or normalized?

Looking at income statement: 2021 tax expense was 201,793,000; 2022 was 188,330,000. The cash tax paid in 2022 (363,996,000) is much higher than tax expense, suggesting timing differences or prior year payments.

This high cash tax in 2022 may not be recurring. However, S&P uses actual cash taxes paid for FFO.

Given both signals are Stable (Signal 1 clearly Stable at -0.024x; Signal 2 at -0.028, which rounds to -0.03 but is technically > -0.03), the classification is **Stable**.

But wait - let me recheck Signal 2 more precisely. -0.0277 is the exact value. Is this ≥ -0.03? Yes, -0.0277 > -0.03. So Stable.

However, there's a nuance: if I use slightly different rounding or if the exact threshold interpretation matters, -0.0277 is very close to -0.03. But mathematically, it's in the Stable range.

Actually, re-reading: "between -0.03 and +0.03 (exclusive)" - so if exactly -0.03, it's Deteriorating. But -0.0277 ≠ -0.03.

Final answer: Both signals are Stable.

<answer>Stable</answer>