The top line of a company's reported financials is the total amount of revenue generated from sales during a given period. It is one of the most important metrics in evaluating the performance of a business as it reflects the ability to bring in income and convert sales opportunities into revenue. The importance of the top line cannot be overstated: it has a direct effect on the profit margin of a company and reveals important strategies and decisions regarding marketing, business development, and production.

For example, a company that focuses on high-volume sales of lower priced products will likely have a higher top line than one which focuses on high-volume sales of higher priced products, although the latter may generate a higher gross profit margin and net income. Thus, the top line is a key indicator of how well the company is managing its sources and minimizing costs.

The top line is a direct result of total sales. It does not take into consideration the company's expenses like production costs, marketing costs, payroll, operating expenses and taxes. To calculate the net income or profit of a business, these costs must be subtracted from the top line figure.

The top line is typically reported quarterly and annually by publicly traded companies, and serves as a barometer of financial health to potential investors, shareholders and the public. It can provide insight on the overall performance of the company, as well as whether the company is able to generate a return on its investments.

To sum up, the top line is an important economic measure of any company’s financial performance and is an invaluable tool in evaluating the success of a business. In other words, the top line reflects if a business is generating income, while the bottom line reflects how much income they generate after all expenses, taxes and other items have been taken into account. It is essential for businesses to comprehend the significance of both their top line and the bottom line to make informed decisions that can help to increase the company’s profits.