Step 1 — Relevant industry  
TenneT Holding B.V. is described as a “transmission system operator.” This fits the Regulated Utilities methodology, specifically electricity transmission/network infrastructure.

Step 2 — Estimate Adjusted_Debt  

Use the baseline formula:

Adjusted_Debt = reported_debt + leases + pension_deficit + hybrid_debt_portion + other_debt_like_items − eligible_cash

Reported debt:
- Long-term borrowings at 2023-01-01: €19,006m
- Short-term borrowings at 2023-01-01: €709m
- Current bank overdrafts at 2023-01-01: €0m

Reported debt = 19,006 + 709 + 0 = €19,715m

Leases:
- Noncurrent lease liabilities: €574m
- Current lease liabilities: €155m

Lease liabilities = 574 + 155 = €729m

Pension deficit:
- Noncurrent recognized liabilities defined benefit plan: €174m

Pension deficit = €174m

Hybrid debt portion:
- Hybrid capital: €2,125m

S&P often gives intermediate equity credit to qualifying hybrids, commonly treating 50% as debt and 50% as equity, absent more detailed terms.

Hybrid debt portion = 50% × 2,125 = €1,062.5m

Other debt-like items:
- No clear guarantees or other debt-like items provided.
- Other financial liabilities could contain derivatives/other items, but without evidence they are debt-like, do not add them.

Other debt-like items = €0m

Eligible cash:
- Cash and cash equivalents at 2023-01-01: €6,547m

Eligible cash = €6,547m

Adjusted_Debt = 19,715 + 729 + 174 + 1,062.5 − 6,547  
Adjusted_Debt = €15,133.5m

Step 3 — Estimate Adjusted_EBITDA  

Reconstruct EBITDA from operating profit:

Reported operating profit/loss = −€976m  
Depreciation and amortization = €1,233m  

EBITDA before adjustments = −976 + 1,233 = €257m

Adjustments:
- Lease adjustment: since lease liabilities are added to debt, add back lease-related depreciation/interest only if separable. The data does not provide ROU depreciation/lease interest split, so no reliable add-back beyond reported D&A.
- Nonrecurring losses: “Other gains/losses” is −€38m and cash flow note identifies losses on disposal of noncurrent assets of €38m. This appears nonrecurring/nonoperating, so add back €38m.
- Joint ventures: share of profit of associates/JVs = €120m is included after operating expenses in arriving at operating activities. S&P may proportionally adjust for JVs, but no JV EBITDA/debt data is available. No proportional EBITDA adjustment made.
- Pension or other normalization: no detailed data to adjust.
- Hybrid distributions are financing/equity distributions, not EBITDA.

Adjusted_EBITDA = 257 + 38 = €295m

Step 4 — Adjusted_Debt / Adjusted_EBITDA  

Adjusted_Debt / Adjusted_EBITDA = 15,133.5 / 295 = 51.30

<answer>51.30</answer>