The US Supreme Court on Thursday lifted a 20-year ruling which had set limits on campaign financing by American businesses. The nine justices ruled that US corporations could dip freely into their general funds to finance campaign ads either in support or against a particular political candidate. The move overturns a ruling made two decades ago that forced companies to only use specially earmarked funds from a political action committee. The Supreme Court also ruled that any campaign ads not financed by the candidate or their party must be clearly marked with the name of the sponsor. Ignoring statements by the administration of President Barack Obama defending the previous law, the court said it did not think using campaign finance limits would lead to corruption. They also rejected the argument that company share-holders could see their money being used in support of political views which they did not agree with. The ruling came in a case about a documentary titled 'Hillary: The Movie' made by a conservative group in 2008 against the White House bid by Hillary Clinton. The case pitted the Federal Election Commission (FEC) against Citizens United, the group that made the biting film but was barred by the FEC from airing ads for it during the 2008 presidential election. The FEC ruled the producers had to conform to existing US laws on campaign financing, which required political adverts to reveal the source of their funding. Federal judges ruled in favor of the FEC, but in a Supreme Court hearing in March last year the justices already appeared to be leaning in favor of loosening federal controls on spending by corporations. 