A politically divided Securities and Exchange Commission is likely to approve a program of whistleblower rewards Wednesday over the opposition of the two Republican commissioners, sources close to the process said.

In what would be a defeat for business groups that have expressed alarm about the program, the SEC is not likely to require that whistleblowers report their allegations to the companies they accuse of wrongdoing, the sources said.

But the agency will probably give whistleblowers a financial incentive to report purported wrongdoing to their own companies in addition to sharing their information with the SEC, one source said. For example, whistleblowers might qualify for larger rewards if they alert the company also, the source said.

In the Wednesday vote, the SEC is set to lay out final rules for a plan to enlist corporate insiders and other informants in the effort to stamp out financial fraud. As part of the Wall Street regulatory overhaul enacted last year in response to the financial crisis, Congress and President Obama declared that whistleblowers are entitled to rewards of 10 percent to 30 percent of the money they help the SEC collect through enforcement actions.

Whistleblowers have long been able to collect rewards for exposing fraud against the government. The new program would formalize the process at the SEC, which polices Wall Street and the financial disclosures of companies traded on the stock markets. In SEC enforcement cases, the victims are typically investors.

Advocates of the rewards say they could be a game-changer in the policing and deterrence of corporate fraud. Executives who consider cooking the books, for example, would be left to wonder whether their employees would alert the SEC — to get rich, if not merely to do the right thing.

Whistleblower advocates say tipsters often suffer retaliation, including the destruction of their careers, and strong financial incentives are needed to encourage them to risk coming forward.

Giving smaller rewards to those whistleblowers who go straight to the SEC without notifying their employer would discourage people from coming forward, said Lynn E. Turner, who has been a corporate board member and chief accountant at the SEC.

“If the SEC pushes people to first report to the company, I think it will result in fewer complaints to the SEC and more complaints going to WikiLeaks,” Turner said.

Business groups have said the incentives could expose corporations to a flood of allegations, including unfounded ones. The groups have argued that employees should first report internally, giving the companies a chance to address the problems instead of bypassing the systems that firms have put in place to field tips and ensure that they are complying with the law.

House Republicans, who hold power over the SEC’s budget, have expressed support for the business groups’ position.

The U.S. Chamber of Commerce, a leading critic of the rewards proposal, does not expect the SEC to require whistleblowers to report their allegations to the company as a condition of receiving a reward, said Thomas P. Quaadman. As a result, problems will be allowed to fester, he said.

“This is another confusing and burdensome rule that will negatively impact the atmosphere to operate as a public company in the United States,” Quaadman said.

Two other sources who have been following the rulemaking process said they did not expect the SEC to require whistleblowers to go through corporate channels. One spoke on condition of anonymity for lack of authorization to speak publicly, and the other to avoid exposing a contact at the SEC.

The debate over whistleblower rewards has been one of the most intense regulators have confronted as they write rules to implement the Dodd-Frank law enacted last year in response to the financial crisis.

In the final rules, the SEC is trying to thread a needle between opposing arguments, and it is unlikely to satisfy either camp, the first source said.