Unlocking value from the ever-widening stream of complex, fast-moving “big data” has generated a great deal of buzz in the C-suite. But often left out of the discussion is how to gain access to this information—much of it sensitive personal data—in the first place. In order for global companies to have the greatest possible access to personal data, consumers need to trust that this information will be well stewarded. Good stewardship means that data will be used for the purposes allowed—and only for those purposes.

Some organizations will excel at creating trust, and some will not. We estimate that those that manage this issue well should be able to increase the amount of consumer data they can access by at least five to ten times in most countries. And if they can generate meaningful insights from this information and execute an effective big-data strategy, the resulting torrent of newly available data could shift market shares and accelerate innovation. This performance boost is what we call the “trust advantage.”

Trust is elusive, however. An example with recent relevance is the revelation that the U.S. National Security Agency has been widely monitoring e-mail, phone calls, Web traffic, private networks, and cloud services—even those previously thought to be encrypted—to fight terrorists. Many have expressed concern that the personal information the U.S. government has collected will be used for other purposes. In the absence of mechanisms to prevent this, there have been efforts to place such severe restrictions on the use of personal information that the original goal—reducing terrorism—could itself be jeopardized.

Without consumer trust, most of the trillions of dollars of social and economic value promised from big data will not be realized. (See “Unleashing the Value of Consumer Data(//www.bcgperspectives.com/content/articles/digital_economy_consumer_insight_unleashing_value_of_consumer_data/),” BCG article, January 2013.) In fact, we estimate that two-thirds of the total value potential stands to be lost if stakeholders fail to establish a trusted flow of personal data. (See “The Value of Our Digital Identity(//www.bcgperspectives.com/content/articles/digital_economy_consumer_insight_value_of_our_digital_identity/),” BCG article, November 2012.)

The good news is that trust can be systematically built and strengthened—if organizations master the internal principles, codes of conduct, compliance mechanisms, and trust metrics involved in stewarding data and holding themselves accountable, and if they communicate transparently with consumers about their actions and performance as data stewards. This will require that policies about data stewardship rest within the C-suite, rather than being relegated to the legal or public-policy department under the guise of privacy or lobbying.