TTIP: Why are the talks taking so long?
The Transatlantic Trade and Investment Partnership (TTIP), which seeks to reduce regulatory barriers between the US and the European Union, is at the end of its 14th round.
Analysts are worried Brexit will slow talks and make a deal this year unlikely.
It's already an agonisingly slow process - negotiations have been going on for three years - and it's unlikely a deal will be struck before the end of the Obama administration.
Critics of TTIP warn a deal would jeopardize European standards, such as food safety, and leave public services at risk of privatization.
We take a look at some of the reasons why the talks are so complicated.
Video journalist: Jeremy Howell
15 Jul 2016