I need to analyze whether Bouygues should utilize hybrid bonds up to S&P Global Ratings' 15% cap of total adjusted capital.

First, let me understand what hybrid bonds are and the equity credit treatment. Hybrid bonds are securities that have both debt and equity characteristics. S&P Global Ratings allows equity credit of up to 15% of total adjusted capital (debt + equity) for hybrid bonds.

Let me calculate Bouygues' financial position from the 2022 annual report (using 2023-01-01 figures which are end of 2022):

**Equity and Debt figures:**
- Equity 2023-01-01: €13,932,000,000
- Long-term Borrowings: €11,586,000,000
- Current Borrowings and Current Portion of Noncurrent Borrowings: €1,361,000,000
- Current Overdrafts and Short Term Borrowings from Banks: €418,000,000

**Total Debt:**
- Long-term borrowings: €11,586M
- Current borrowings portion: €1,361M
- Short-term bank borrowings: €418M
- Total debt = €11,586M + €1,361M + €418M = €13,365M

Wait, let me also check if there are lease liabilities that might be considered debt-like:
- Noncurrent Lease Liabilities: €2,107M
- Current Lease Liabilities: €498M

For credit rating purposes, lease liabilities are typically considered debt-like obligations.

**Total Adjusted Capital calculation:**
- Total equity: €13,932M
- Total debt (borrowings + leases): €13,365M + €2,605M = €15,970M
- Or just borrowings: €13,365M

Let me use a broader definition. For S&P purposes, "debt" typically includes interest-bearing obligations.

Actually, let me look at "Net Debt" which is given as €7,440M at 2023-01-01. This suggests gross debt minus cash.

From the balance sheet, total liabilities are substantial. Let me focus on what S&P would consider:

Total adjusted capital = Debt + Equity

If we use total equity €13,932M and need to determine debt:

Looking at the liability structure:
- Long-term borrowings: €11,586M
- Current borrowings: €1,361M
- Current overdrafts/short-term: €418M
- Lease liabilities (noncurrent): €2,107M
- Lease liabilities (current): €498M

Total interest-bearing debt ≈ €15,970M

Total adjusted capital = €13,932M + €15,970M = €29,902M

15% of total adjusted capital = 0.15 × €29,902M = €4,485M

Or if we use a narrower debt definition (just borrowings without leases):
Total debt = €13,365M
Total adjusted capital = €13,932M + €13,365M = €27,297M
15% cap = €4,095M

**Analysis of Bouygues' situation:**

1. **Current leverage and credit metrics:**
   - Net debt increased significantly from €941M to €7,440M (2022-01-01 to 2023-01-01)
   - This is a massive increase in leverage
   - The company made large acquisitions (cash flows used in obtaining control of subsidiaries: €6,269M in 2022 vs €382M prior year)

2. **Interest rate environment (2022):**
   - Swap rates turned sharply positive in 2022 (5Y: 1.726%, 7Y: 1.806%, 10Y: 1.927%)
   - This is a dramatic shift from negative rates in 2020-2021
   - Corporate bond spreads (iShares Core Euro Corp Bond): 1.085% average, with bear case 1.2846%
   - Sub-senior non-financial IG: 2.295% average

3. **Rationale for hybrid bonds:**
   - Hybrids can provide equity credit for rating purposes, improving leverage metrics
   - In a rising rate environment (2022), locking in long-term financing is important
   - Hybrids typically have coupon reset features and long maturities (often perpetual or 50+ years)
   - They can be cheaper than pure equity but provide equity-like credit treatment

4. **Bouygues' specific situation:**
   - Significant acquisition activity in 2022 (€6.3B for subsidiaries)
   - Goodwill increased from €7,446M to €12,626M - indicating major M&A
   - Revenue grew strongly: €37.6B to €44.3B
   - Operating profit improved: €1.69B to €1.96B (recurring)
   - But net profit declined: €1.305B to €1.131B

5. **Optimal utilization of hybrid capacity:**
   - The 15% cap is a maximum, not a target
   - Full utilization (100% of cap = 15% of adjusted capital) would mean issuing hybrids up to the maximum allowed equity credit
   - Partial utilization provides some benefit without maximizing structural complexity

Key considerations:
- **High leverage increase**: Net debt went from €941M to €7,440M - nearly 8x increase
- **Acquisition-driven growth**: The company is clearly in expansion mode
- **Rising interest rates**: Makes fixed-rate hybrid issuance attractive to lock in before further rises
- **Credit rating protection**: With increased leverage, protecting the credit rating becomes more important

Given:
- The substantial increase in leverage due to acquisitions
- The rising interest rate environment making long-dated fixed income attractive for issuers
- The need to manage credit metrics after a major balance sheet expansion
- Strong operational performance (revenue growth, operating profit improvement)

Bouygues should utilize a significant portion of the hybrid capacity to:
- Optimize its capital structure
- Provide rating agency equity credit to offset the leverage increase
- Take advantage of still-reasonable corporate bond rates before further increases

However, full 100% utilization may be excessive because:
- Hybrids are more expensive than senior debt
- They add structural complexity
- Market capacity for hybrids may be limited
- Too much hybrid debt can concern investors

Given the significant leverage increase and the clear benefit of equity credit for rating purposes, but also considering cost and complexity, **75%** utilization seems appropriate. This provides substantial rating benefit while maintaining some headroom and not maximizing structural complexity.

Actually, reconsidering: with net debt increasing so dramatically (from €941M to €7,440M), and the company clearly needing to manage its credit profile after major acquisitions, utilizing the hybrid capacity more fully makes sense. The 2022 rate environment suggests locking in long-term financing.

Let me think about this more carefully. The question asks what extent the company should utilize the cap. Given:
1. Major balance sheet expansion (assets from €44.6B to €60.6B)
2. Significant goodwill increase (acquisitions)
3. Need to preserve credit metrics
4. Rising rate environment - hybrids can provide long-duration funding

75% or 100%? 

With the dramatic increase in leverage and the clear strategic use of debt for acquisitions, maximizing hybrid equity credit (100%) would provide the most rating benefit. However, hybrids are typically more expensive than senior debt, and full utilization might be seen as aggressive.

Given that Bouygues is an investment-grade company (S&P typically rates it BBB+ or similar), and the significant leverage increase, using **75%** of the capacity provides meaningful credit support while being prudent.

Wait - let me reconsider the market data. The swap curves show rates have risen dramatically. In a higher rate environment, the coupon on new hybrids would be higher. But the equity credit benefit is more valuable when leverage is elevated.

Given the substantial increase in net debt and the need to maintain investment grade ratings, I believe **75%** utilization is appropriate - high enough to meaningfully support credit metrics, but not so high as to be seen as aggressive or to create excessive cost.

Actually, looking more carefully at the numbers: the company just did massive acquisitions. It needs to deleverage or at least stabilize its credit metrics. Hybrid equity credit helps this directly. The 15% cap is there for a reason - it's considered a prudent maximum. Using 75% of that cap (i.e., getting equity credit equal to 11.25% of adjusted capital) provides significant benefit.

I'll go with **75%** as it balances the need for credit support with cost and complexity considerations.

<answer>75%</answer>