The CBI says the UK needs to keep its place within the European Union to push for freer trade for its businesses.
The business lobby group says the UK should use the EU to help rebalance the economy towards exports and create new trade deals.
It is pushing for a new free trade deal between Europe and the US.
The CBI says although the EU and US have relatively open economies, there are many examples of obstacles to trade.
These include tariff costs and mismatched regulations, which form what it says are significant burdens on firms on both sides of the Atlantic.
It is undertaking a major project to flesh out what the UK's global role should look like in a new Europe.
It wants to explore ways in which the UK can remain a leading location to do business globally, particularly by expanding export markets for high-growth small and medium-sized firms, without losing access to the EU single market.
The CBI's director-general, John Cridland, said it was crucial for the UK to keep its place within Europe; "The UK has ensured its values of free and open trade have been at the heart of Europe over the last 40 years, helping to create one of the biggest successes of the European Union - the single market.
"It's essential we stay at the table to bang the drum for businesses and defend our national interest, particularly protecting our world-class financial services industry to maintain our competitiveness internationally."
He added that President Barack Obama and the EU's political leaders needed to work to eliminate barriers to trade, which he said one study showed could save as much as 122bn euros (£100bn, $161bn) a year in business costs.