To determine the appropriate extent to which Bouygues should rely on hybrid bonds in its capital structure, we must analyze the company's financial health, leverage, interest coverage, and the prevailing market conditions provided.

**1. Financial Health and Leverage Analysis:**
*   **Equity vs. Debt:** As of 2023-01-01, Total Equity is €13,932 million. Total Liabilities are approximately €46,663 million (Total Assets €60,595m - Equity €13,932m).
*   **Net Debt:** The report states Net Debt increased significantly from €941 million in 2022 to €7,440 million in 2023. This increase is largely driven by acquisitions (Cash flows used in obtaining control of subsidiaries: €6,269 million).
*   **Leverage Ratio:** Net Debt / Equity is approximately 0.53 (7,440 / 13,932). This is a moderate leverage ratio. While not distressed, the sharp increase in net debt suggests a need for careful capital management to maintain investment-grade ratings.
*   **Interest Coverage:** Profit from Operating Activities (EBIT) is €1,872 million. Interest Expense is €231 million, and Interest on Lease Liabilities is €62 million. Total interest burden is roughly €293 million. The EBIT/Interest coverage ratio is approx 6.4x (1,872 / 293). This is a healthy coverage ratio, indicating the company can comfortably service its debt. However, hybrid bonds typically carry higher coupons than senior debt, which would reduce this coverage.

**2. Nature of Hybrid Bonds:**
Hybrid bonds are instruments with characteristics of both debt and equity. They are often used to:
*   Strengthen the equity base (as they can be treated as equity for rating agency purposes).
*   Provide tax shields (interest is often tax-deductible).
*   Offer flexibility (coupon deferral options).
However, they are more expensive than senior debt due to their subordinated status and higher risk for investors.

**3. Market Conditions (2022):**
*   **Interest Rates:** The swap curves show a dramatic shift from negative/low rates in 2020-2021 to significantly positive rates in 2022 (e.g., 10Y Swap Average 1.927%). This indicates a rising cost of capital environment.
*   **Credit Spreads:** The iBoxx EUR Non-Financial IG spread increased from 1.298% in 2021 to 2.295% in 2022. This widening spread means issuing any form of debt, including hybrids, has become more expensive.
*   **Implication:** In a rising rate and widening spread environment, companies generally prefer to minimize expensive financing. Hybrid bonds, being subordinate, would command a significant premium over senior debt. Given Bouygues' already healthy interest coverage and moderate leverage, there is no urgent distress signal requiring the equity-like buffer of hybrids to satisfy covenants or rating agencies immediately, especially at a high cost.

**4. Strategic Fit for Bouygues:**
*   Bouygues is a diversified industrial group (Construction, Media, Telecom). These sectors are capital intensive but generate stable cash flows.
*   The company has a strong operating profit and positive cash flow from operations (€2,978 million).
*   The recent spike in Net Debt is due to M&A. Typically, after large acquisitions, companies focus on deleveraging or maintaining stable leverage.
*   Relying heavily on hybrids (50-100%) is unusual for a non-financial industrial company unless it is highly leveraged or seeking specific regulatory capital treatment (more common in banks/insurers).
*   A 0% reliance might be too conservative if the company wants to optimize its Weighted Average Cost of Capital (WACC) by utilizing the tax shield of debt, but hybrids are not the most efficient debt tool compared to senior debt when spreads are wide.
*   However, the question asks for the extent of *reliance*. Most industrial companies have little to no hybrid debt in their core structure, relying instead on senior bonds and bank loans. Hybrids are niche.
*   Given the high cost of capital in 2022 (high swaps, high spreads), issuing expensive hybrid debt is unattractive. The company has sufficient equity buffer (Equity/Assets ~23%).
*   Therefore, the optimal strategy is to minimize reliance on this expensive, complex instrument. Standard corporate finance theory for an industrial firm with investment grade metrics suggests minimal to no use of hybrids unless specific strategic reasons exist (which are not evident here beyond general M&A funding, which was likely funded by senior debt or cash given the net debt jump).

Comparing the options:
*   **100%, 75%, 50%:** These levels are extremely high for an industrial conglomerate and would unnecessarily inflate the cost of capital, especially in a high-rate environment.
*   **25%:** This might be considered for a company seeking to aggressively manage leverage ratios for rating purposes, but Bouygues' leverage is not critical.
*   **0%:** This is the most standard approach for industrial firms with strong cash flows and moderate leverage. They rely on senior debt and equity. The cost of hybrids in 2022 makes them particularly unattractive.

Therefore, the company should not rely on hybrid bonds.

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