The act defines political intelligence as information "derived by a person from direct communications with an executive branch employee, a Member of Congress, or an employee of Congress; and provided in exchange for financial compensation to a client who intends, and who is known to intend, to use the information to inform investment decisions."

The report by the U.S. Government Accountability Office targets the role of political intelligence in financial markets. The Stop Trading on Congressional Knowledge (STOCK) Act of 2012, an effort to stop members of Congress from benefitting personally on insider information, required the accountability office to release the report.

A highly anticipated report published today by the investigative arm of Congress addresses the murky arena of "political intelligence" but leaves unanswered many questions about the size and power of the shadowy Washington information gathering industry.

Unlike federal lobbyists, political intelligence consultants aren't required to register with Congress and disclose their activities and income. The GAO report marks the first time a government agency formally reviewed the secretive industry in an attempt to shed light on it. But definitive information on the business of political intelligence gathering was sparse in the report.

"The prevalence of the sale of political intelligence is not known and therefore difficult to quantify," the 34-page GAO report says. "The extent to which investment decisions are based on a single piece of political intelligence would be extremely difficult to measure."

Senator Chuck Grassley (R-Iowa) and Representative Louise Slaughter (D-N.Y.), who both fought for a political intelligence reporting provision in the STOCK Act, said in a joint written statement that the report illustrates the "dire need" for disclosure requirements. The pair said they plan to introduce political intelligence disclosure legislation in this Congress.

"When a political intelligence professional is paid to gather inside information from congressional or agency sources that can be used to make investment decisions, that professional should have to register and disclose his or her activities to the public," Grassley and Slaughter said.

Although disclosure would increase transparency in the political intelligence industry and, according to the U.S. Securities and Exchange Commission, help with insider trading cases, Congress has a bevy of matters to address before it could become a reality, the GAO report says. Congress must examine cost, structure, as well as the definition of political intelligence, among other issues, according to the office. The GAO notes that terms like "direct communication" and "investment decision" don't have agreed upon meanings.

Wiley Rein of counsel Robert Walker, a former chief counsel and staff director of the U.S. Senate and U.S. House of Representatives ethics committees, said the definition of political intelligence is "problematic" and "overly broad," making regulation difficult.

"The devil is in the definition," he said.

For the report, the GAO had 34 "semi-structured interviews" with several entities, including regulatory agencies, eight political intelligence firms and four law firms that gather political intelligence. But the office didn't disclose which firms were interviewed.

All four law firms told the GAO that the political intelligence they provide usually isn't a single piece of information, but rather part of a package that includes policy analysis, research and opinions. And each of the firms said they don't know how clients use the information they gather.

Of the four firms, three said they don't specifically record political intelligence income. Only one has policies to combat knowingly selling information that isn't authorized for public consumption.

A couple of the firms said the demand for political intelligence is on the rise, noting clients' interest in the health care reform legislation and U.S. budget uncertainty.

Craig Holman, government affairs lobbyist for government watchdog Public Citizen, said in a written statement that his organization will push for legislation that brings transparency to political intelligence gathering.

"The political intelligence industry is flourishing, enriching itself and clients in the stock market, yet the report notes that it could not document who these people are or how much they profit," he said. "Without full transparency of the activity of these political intelligence consultants and their clients, it is nearly impossible to know if they are trading on illegal insider information."