Explanation

Debt as a proportion of total capital is typically greatest during the Mature stage of a company's life cycle. Here's why:

Life Cycle Stages and Capital Structure:

1. Start-up Stage:

   • Companies in the start-up phase have limited access to debt financing
   • High business risk and uncertainty make lenders hesitant
   • Most financing comes from equity (founders, angel investors, venture capital)
   • Debt-to-capital ratio is typically low

2. Growth Stage:

   • Companies begin to establish track records and generate cash flows
   • Some debt financing becomes available, but still limited
   • Companies may use debt to finance expansion, but equity remains significant
   • Moderate debt-to-capital ratio

3. Mature Stage:

   • Companies have stable cash flows and established market positions
   • Lower business risk makes debt financing more attractive and accessible
   • Companies often increase leverage to:
     • Take advantage of tax shields from interest expense
     • Return capital to shareholders through dividends and buybacks
     • Finance acquisitions
   • Debt-to-capital ratio is typically highest in this stage

Key Factors:

• Cash flow stability: Mature companies have predictable cash flows that can service debt obligations
• Asset base: Mature companies often have substantial tangible assets that can serve as collateral
• Tax considerations: Interest expense is tax-deductible, making debt financing more attractive for profitable mature companies
• Financial flexibility: Mature companies can afford higher leverage due to lower business risk

Therefore, among the three options, the Mature stage (Option C) is when debt as a proportion of total capital is most likely greatest.