The US ranks third globally for growth opportunities behindChinaandIndia, but second behindChinafor perceived barriers to entry, according to a new global report by international legal practice Allen & Overy.

Allen & Overy conducted in-depth research among 1,000 business leaders from large international companies across 19 countries. TheOpportunities and challenges reportis the first report in the50 Degrees Eastseries looking at howAsia's rapid growth and development is expected to influence business decision making in the future.

When asked to identify the three markets that presented the best opportunities for growth for their business, 23% of respondents named the US, compared to 44% forChinaand 34% forIndia.

However, the US also came second only toChinawhen firms were asked to identify the three most difficult markets to enter, with 19% picking the US compared to 21% forChina. The regulatory environment is regarded as the main barrier to entry in both countries.

An analysis of investment flows showed that FDI inflows to the US were a world-leading$228.2 billionin 2010, compared to$324.6 billionin 2008 and$266.0in 2007, while FDI outflows reached$329.9 billionin 2010, compared to$393.9 billionin 2008.

Portfolio inflows were$946.8 billionin 2009, lower than the previous peak in 2006 of$1.1 trillion, but much higher than the 2005 level of$433.5 billion. Portfolio outflows were$1.7 trillionin 2009, higher than the previous peak of$1.4 trillionin 2006.

In terms of threats to the global economy, fears about the Eurozone sovereign debt default were greater among businesses based in the US. More than half (52%) said this was their main concern, compared to only 36% of those based inEurope.

However, when it comes to economic influence,North Americais surprisingly second from bottom, just aboveEuropebut belowSouth America,Africaand theMiddle East.Asia Pacificis top of the rising economic influence league.