Acciona has a clear rationale to use hybrids, but not to the full S&P cap.

Key credit considerations:

- **Capital intensity is high and rising.** 2022 investing cash outflow was about **€1.94bn**, with purchases of PPE/intangibles/investment property/other noncurrent assets of about **€2.20bn**, more than double the prior year. Property, plant and equipment increased from **€8.07bn to €9.49bn**, reflecting continued expansion, likely linked to infrastructure and renewable-energy assets.
- **Free cash flow after capex was negative.** Operating cash flow was strong at **€1.65bn**, but this did not cover investing cash outflows. This means external funding remains important for growth.
- **Leverage/funding needs are meaningful.** Gross financial debt-like items increased materially. Bonds and other negotiable securities rose to about **€4.24bn** current/noncurrent, loans to about **€3.18bn**, and lease liabilities to about **€0.51bn**. Cash is substantial at **€2.36bn**, but the group is still funding a large asset base and growth program.
- **Earnings and cash flow improved strongly.** Revenue rose to **€11.20bn**, operating profit to **€1.33bn**, and operating cash flow to **€1.65bn**. This supports investment-grade resilience and argues against a maximum 15% hybrid recommendation.
- **Hybrid market cost is less attractive than in 2020–2021.** Euro rates increased sharply in 2022, with 5Y–10Y swaps around **1.7%–1.9%**, and non-financial IG subordinated spreads around **2.3%** on average. Hybrid issuance would likely be more expensive than existing senior debt, so using the full S&P cap would not be cost-efficient unless rating preservation were highly dependent on it.
- **There already appears to be hybrid/preferred/bond-like capital in the structure.** The line “Participaciones Preferentes Obligaciones y Otros Valores Negociables” is large, though not all necessarily hybrid. The company is already familiar with capital markets and subordinated/hybrid-like instruments, which supports some incremental use, but the current starting point means it should not over-issue.
- **Business risk profile is mixed but infrastructure/renewables-oriented.** Acciona has exposure to energy and infrastructure activities with relatively supportive long-term fundamentals, but not all cash flows are fully regulated. This makes leverage flexibility valuable, especially during heavy growth investment.

Overall, Acciona’s profile points to **moderate-to-high but not extreme** hybrid need. The company has substantial capex and negative post-investment cash flow, so 0% or 3.75% would likely understate the usefulness of hybrids. However, earnings momentum, liquidity, and the absence of evidence of acute downgrade risk make 15% too aggressive. The best balance is **7.5% of total adjusted capital**, providing meaningful S&P equity credit and leverage support without excessive reliance on costly hybrid capital.

<answer>7.5%</answer>