**Step 1 – Identify the relevant industry**  
HERA S.P.A. is a multi‑utility (electricity, gas, water) operating in Italy. This falls under the **Regulated Utilities** sector in the S&P methodology.

**Step 2 – Estimate Adjusted Debt**  
Following the S&P‑adjusted debt formula for regulated utilities:

\[
\text{Adjusted Debt}= \text{Reported debt} + \text{Leases} + \text{Pension deficit} + \text{Other debt‑like items} - \text{Eligible cash}
\]

- **Reported debt** (financial liabilities, excl. leases)  
  – Non‑current financial liabilities: €5,689.9 M  
  – Current financial liabilities: €650.1 M  
  → Reported debt = €6,340.0 M  

- **Leases** (balance‑sheet lease liabilities)  
  – Non‑current lease liabilities: €55.1 M  
  – Current lease liabilities: €21.3 M  
  → Lease liabilities = €76.4 M  

- **Pension deficit** (non‑current provisions for employee benefits) = €92.0 M  

- **Other debt‑like items** (other long‑term provisions) = €565.6 M  

- **Eligible cash** (cash & cash equivalents at year‑end) = €1,942.4 M  

\[
\text{Adjusted Debt}=6,340.0 + 76.4 + 92.0 + 565.6 - 1,942.4 = €5,131.6\text{ M}
\]

**Step 3 – Estimate Adjusted EBITDA**  

Start from the reported operating profit and add back depreciation, amortisation and provisions:

\[
\text{EBITDA}= \text{Operating profit} + \text{Depreciation, amortisation \& provisions}
= €533.8\text{ M} + €667.1\text{ M}= €1,200.9\text{ M}
\]

Apply the S&P adjustments:

- **Non‑recurring gains** (capital gains & other non‑monetary items): €41.6 M → subtract  
- **Change in provisions** (release of provisions): –€27.8 M → subtract  

\[
\text{Adjusted EBITDA}= €1,200.9\text{ M} - €41.6\text{ M} - €27.8\text{ M}= €1,131.5\text{ M}
\]

- **Joint‑venture proportional EBITDA** (share of profit from associates): +€10.0 M  

\[
\text{Adjusted EBITDA}= €1,131.5\text{ M} + €10.0\text{ M}= €1,141.5\text{ M}
\]

**Step 4 – Compute the ratio**

\[
\frac{\text{Adjusted Debt}}{\text{Adjusted EBITDA}}= \frac{5,131.6}{1,141.5}= 4.4955
\]

Rounded to two decimal places → **4.50**.

<answer>4.50</answer>