Big business is shoveling more money than ever into U.S. political campaigns, with Wall Street donations way up, a watchdog group said on Tuesday.

The securities and investment industry -- which includes brokerages, hedge funds and private equity firms -- registered the sharpest increase in giving since 2004 among all industry sectors studied by the Center for Responsive Politics.

Record-breaking contributions from the nation's biggest political givers are the result of a wide-open race for the White House and last year's power shift in Congress, said Sheila Krumholz, the nonpartisan center's executive director.

There is an intensity to the fund raising for 2008 that we've never seen before, which means the candidates and parties will be all the more beholden to big donors, she said.

The nonprofit center analyzes campaign finance and lobbying records at the Federal Election Commission (FEC), a government agency that enforces U.S. campaign finance law.

The analysis includes contributions to federal candidates and parties from individuals working in an industry and from associated political action committees.

In both presidential and congressional contests, Democrats are benefiting more than Republicans from the surge in business donations, with 57 percent of giving from typical big donors going to Democrats versus 43 percent in 2006 and 2004.

More money is coming in from lawyers than from any other sector, as usual. But the biggest increase in giving since 2004 is coming from financiers, whose donations are up 91 percent.

Steep increases are also coming from the real estate industry, Hollywood, healthcare professionals and insurers.

Industries with small increases, and even some decreases, tend to be past Republican allies, said the center's analysis.

Automakers have been staunch Republican supporters since 1990, but in this campaign cycle their giving is down 20 percent. Declines are also evident among grocers, food processors and telephone companies, the center said.

Only small increases are being seen among Republican backers such as builders and defense and aerospace firms. The oil and gas industry's contributions are up 15 percent, well below the average for big industries, the center said.

Democratic donors seem unusually mobilized for this election. But those industries who've traditionally given to Republicans seem to be either nursing their wounds from '06 or sitting this election out, Krumholz said.

Wall Street's favorite presidential candidate, based on the latest FEC disclosures from October 29, was Democratic New York Sen. Hillary Clinton. Close behind her in donations from financiers were Republican former New York Mayor Rudolph Giuliani and Democratic Illinois Sen. Barack Obama.

Next were Republican former Massachusetts Gov. Mitt Romney, Democratic Sen. Christopher Dodd of Connecticut, Republican Sen. John McCain from Arizona, Democratic former North Carolina Sen. John Edwards and Democratic New Mexico Gov. Bill Richardson.

The biggest donors in the securities and investment sector, as of October 29, were the brokerage firms Goldman Sachs, Morgan Stanley, UBS, Merrill Lynch, Lehman Brothers and Credit Suisse.

Also among the sector's top contributors were hedge funds and private equity firms Bain Capital, SAC Capital Advisers, Fortress Investment Group and Blackstone Group.

There's no question that hedge funds and private equity firms have ramped up their political giving in the last couple of years as Congress looks seriously at raising their taxes, said Massie Ritsch, spokesman for the Center for Responsive Politics.

Lawmakers are considering proposals to more than double the tax rate on the carried interest gains of senior partners at private equity firms that buy and sell businesses.

(Reporting by Kevin Drawbaugh; Editing by Tim Dobbyn)