Why is comprehensive income important to investors?

Comprehensive income is significant to investors primarily because it offers insights into all changes in equity arising from non-owner transactions. This broad view encompasses not just the traditional net income, which reflects the profit generated from operations, but also includes other comprehensive income items such as unrealized gains and losses on certain types of investments, foreign currency translation adjustments, and pension liability adjustments.

Understanding comprehensive income helps investors assess the overall performance of a company beyond what the net income figure can provide. It captures the complete picture of financial performance and reflects more accurately how a company’s operations and external factors have impacted its financial position. This information is vital for investors who are interested in understanding not only how much profit a company made but also how various economic events and transactions outside of typical operations can affect the company’s equity.

The other choices do not capture the comprehensive aspect of income that is crucial for assessing a company's performance and financial standing for investors. For example, a detailed breakdown of operational costs focuses solely on costs instead of overall income, summing only net income ignores comprehensive aspects, and excluding one-time gains or losses limits the analysis to a narrower view of financial performance.