A company's corporate reputation is worth 26% of its market cap, according to a study released this week by Echo Research and Reputation Dividend.

Apple has the most potent corporate reputation, worth 58% of its shareholder value, according to the study. The reputations of ExxonMobil and Chevron followed in the rankings, at 56% of shareholder value each. Companies with the least valuable reputations included Best Buy, Sara Lee, and Sears Holdings.

"There's a lot of money tied up in corporate reputation, and for a company like Apple, there's an enormous value at risk," said Simon Cole, founding partner of Reputation Dividend.

Phillip Morris International, Procter & Gamble, McDonald's, Walt Disney, IBM, Intel, and Google round out the top 10 companies with the most potent reputations. Meanwhile, E*Trade Financial, Family Dollar Stores, SuperValue, Coventry Health Care, Boston Scientific, Dean Foods, Advanced Micro Devices, and Sears Holdings were among the companies with the least potent reputations.

The US Reputation Dividend study examined how corporate reputation contributes to shareholder value for more than 260 companies. Overall, reputation comprises more than $3 trillion of market cap in the S&P 500 Index, the study found. Market cap is defined as the total value of tradable shares of a publicly traded company.

The study looked at a variety of components of corporate reputation, including employee engagement and management, and how much they influence investors' assessment of companies.

However, the companies with the most valuable corporate reputations are not necessarily the most favorable from a consumer's perspective, Cole explained. "There are companies that have strong reputations among consumers, but they're not always being perceived by things that actually matter to the investors' community," he said.

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