In a hotly contested decision that's seen as a big win for the New York Stock Exchange, Securities and Exchange Commission Chairman William Donaldson has pushed through a new rule that would require investor orders to buy or sell stock be filled at the best price, as long as the order can be executed immediately, the Wall Street Journal reported.

Known as the order-protection rule, it will apply to all marketplaces, including the Nasdaq Stock Market and will require markets to get investors the best price, even if that means going to a competing market to fill the order, the Journal reported.

The SEC's two-hour meeting was described as tense, with Donaldson voting for the rule against the objections of fellow Republican commissioners. The move also resulted in a string of rebukes from congressional allies, which come at a time when Donaldson has been criticized by business about the agency's approach to regulation, the Journal reported.

The NYSE had worried about a more aggressive proposal the SEC had suggested late last year and the exchange successfully lobbied the SEC and Donaldson (once the head of the Big Board) to kill that plan, which would have guaranteed price protection on every stock order. Many saw that proposal as a potentially fatal strike at the NYSE as it would have eliminated the need for floor brokers and diminished the role of the specialists who oversee the Big Board's stock auctions, the Journal reported.

Electronic marketplaces, including the Nasdaq, are seen as being on the losing side of the new plan. Nasdaq had lobbied the SEC to allow investors trade on whichever market they want, regardless of whether it offered the best price, the Journal reported.

The SEC's vote sets up a certain showdown with Congress. Following the vote, Sen. Richard Shelby, R-AL, who chairs the Senate Banking Committee, issued a critical statement, saying the vote "reinforces what appears to be a disturbing trend of actions that have resulted in split decisions." While Shelby didn't criticize the passage of the rule itself, he said the "splits dilute the actions of the commission and undermine their authority to speak as a unified body."