WASHINGTON – The millionaires, billionaires and companies giving big sums to political committees supporting Mitt Romney, Newt Gingrich and Barack Obama have important business with the next president. Some are already in trouble with the government. Some are pressing for new laws or regulations that would benefit their interests in energy, mining and high finance.

The Associated Press reviewed financial reports, regulatory filings, court records, public statements and more to identify favors that the biggest donors so far in the presidential campaign might want in return for their contributions worth $100,000 or more. In some cases, these donors have given $1 million or more to help Obama’s challengers or the president.

An exhaustive review of their motives is nearly impossible, since new federal rules governing such contributions allow donors to effectively remain anonymous if they funnel cash into the campaign through corporate partnerships or other mechanisms that can frustrate investigation.