To determine the extent to which Fortum Oyj should utilize hybrid bonds relative to S&P Global Ratings' 15% cap, we must analyze its capital structure and the current market environment for hybrid issuance.

1. **S&P Equity Credit Cap Calculation**: 
   S&P limits the equity credit of hybrids to a maximum of 15% of Total Adjusted Capital (TAC), where TAC = Debt + Equity. 
   From the 2022 balance sheet:
   - Total Equity = €7,737 million
   - Total Liabilities = €15,905 million
   
   S&P typically considers only interest-bearing financial debt for its Debt calculation, excluding operational liabilities like trade payables, provisions, and margin liabilities. Estimating interest-bearing debt from the reported line items:
   - Noncurrent financial liabilities: €3,658m + €756m = €4,414m
   - Current financial liabilities: €4,127m + €3,973m = €8,100m
   - Lease liabilities (included in repayments): ~€1,000m estimated
   - Other operational liabilities (payables, provisions, margin liabilities) = ~€2,400m
   
   Adjusted Financial Debt is roughly €13.5 billion. 
   TAC = €13.5b (Debt) + €7.7b (Equity) = €21.2 billion.
   The 15% cap on TAC translates to: 0.15 * €21.2b = €3.18 billion.

2. **Market Conditions for Hybrids**: 
   Hybrid bonds are perpetual, deeply subordinated, and carry mandatory deferral triggers. Their coupon is typically priced at a significant spread above senior unsecured bonds. 
   Looking at the provided 2022 market data:
   - The 5Y, 7Y, and 10Y swap curves have aggressively risen to ~1.7% - 1.9%, reflecting a high-interest-rate environment.
   - Corporate bond spreads (iShares Core Euro Corp Bond and iBoxx EUR Non-Financial IG) have widened considerably, with the Sub-Sen Delta for Non-Financial IG reaching 2.295% in 2022.
   This implies the all-in cost for a hybrid issuance would be extremely prohibitive, likely exceeding 5-6%, which is exceptionally expensive for utility capital.

3. **Company's Financial Profile & Need for Hybrids**: 
   - Fortum is an investment-grade utility (historically BBB/Baa1 range). Hybrids are typically used by utilities to boost return on equity and maintain rating metrics without issuing common equity.
   - However, Fortum's 2022 financials are dominated by massive impairments and losses from discontinued operations (Russian segment), leading to a net loss of €10.29 billion. 
   - The company is undergoing radical deleveraging and structural changes, selling assets and reducing its balance sheet from €149.6 billion to €23.6 billion. 
   - In such a high-cost environment and amidst a major restructuring, issuing deeply subordinated, high-coupon hybrid bonds would be value-destructive. The need for "cheap" equity padding is outweighed by the exorbitant cost and the fact that the company is actively shrinking its capital base and focusing on reducing financial liabilities.

Given the extremely elevated financing costs in 2022, the company's distressed earnings profile, and the active deleveraging, Fortum should practically avoid issuing expensive hybrid bonds entirely. While the theoretical cap allows for roughly €3 billion, utilizing 0% of this cap is the most prudent and likely real-world decision to avoid punitive financing costs.

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