CNN Money: What Trump can learn from Rex Tillerson, his secretary of state pick

While Trump's holdings are more complex, Tillerson's plan provides good guidance for Trump, said Larry Noble, general counsel of the Campaign Legal Center, a nonpartisan, nonprofit government watchdog group.

"It looks like they really attempted to reach an agreement that will take care of a lot of the ethical concerns," Noble said.

The full scope of Tillerson's plan isn't entirely clear yet, Noble added. He stressed that for a trust to be truly blind, Exxon must have no control over the money manager. But Noble is cautiously optimistic. Exxon said Tuesday that the money would be managed "consistent with government ethics rules."

The effort to eliminate conflicts of interest will ultimately cost Tillerson about $7 million in lost compensation, but Noble said that wealthy business people often have to make some sacrifices before entering public service.

"I don't feel sorry for Tillerson; he's still ending up very well off," Noble said. "But it does show that you do have to change your behavior if you do want to go into the government."