Americans' trust in institutions of all kinds dropped last year as persistently high unemployment sapped people's confidence in business and government, a newly released study found.

The decline in trust in business in the United States stood in contrast to an overall worldwide increase, driven by surging confidence in rapidly developing economies including Brazil and India, the Edelman Trust Barometer found.

Just 46 percent of Americans said they trusted business, down from 54 percent in 2009, the study found, reversing a sharp bounce in confidence that came in the wake of a brutal financial crisis.

The rebound last year was a little bit of euphoria, 'We've got through the worst of it,' and a little bit of a dead-cat bounce, said Matthew Harrington, chief executive of Edelman U.S., the public relations firm that performed the study, which was released on Tuesday.

What we have got this year is more of the reality that this is going to be a long slog, Harrington said.

Worldwide, some 56 percent of respondents said they trusted business, up from 54 percent the pervious year. Respondents in Brazil, India and France drove the overall increase in confidence.

In Brazil, some 81 percent of respondents said they trusted business, up from 62 percent a year ago.

It's a clear sense of optimism, and it's speaking to the fact that their economies are doing well, that businesses -- both home-grown as well as businesses from abroad -- are investing in their countries, Harrington said.

After briefly declining in 2009 during the recession, Brazil's economy snapped back in 2010, growing at a estimated 7.4 percent rate. By contrast, the U.S. economy is struggling with persistently high unemployment -- which has remained above 9 percent for 20 months -- and some analysts look for GDP to grow around 2.5 percent this year.

BANKS SLIDE, AUTOMAKERS SOAR

The public trust in banks plunged in the wake of a crisis that saw huge financial institutions including Bank of America and Citigroup Inc turn to Washington for financial support. Just 25 percent of Americans and 16 percent of Britons said they trusted banks to do the right thing.

In contrast, people in the United States, the United Kingdom, China and India said they trusted the auto sector, following the successful initial public offering of General Motors Co. That marked a sharp shift for an industry that in the United States had also been put on life support by the government during the downturn.

That change, Harrington said, reflected a belief among the public that automakers were starting to tackle their problems.

If you look at the last year, the auto industry has been a bit of a phoenix rising from the ashes, not only in getting their financial house in order, but also innovating, placing some real bets and R&D dollars on hybrids, electric (vehicles), Harrington said.

In addition to the GM IPO, the past year has seen automakers unveil energy-efficient electric vehicles including GM's Chevy Volt and Nissan Motor Co's Leaf, which use less fuel and emit less carbon dioxide than traditional cars.

Respondents expressed the most confidence in the tech industry, which was also the top ranked sector last year. The findings are based on a telephone survey of 5,075 college-educated, upper-income people, in 23 countries surveyed from October through January.

(Editing by Steve Orlofsky)

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