One of the world's biggest multinational trade deals, covering 40% of the global economy, has been signed in New Zealand. The Trans-Pacific Partnership (TPP) is meant to facilitate trade and investment between 12 countries across the Pacific Rim. It’s already taken five years of negotiations, and now needs to be ratified by the member-nations that include the US, Japan, Malaysia, Vietnam, Singapore, Brunei, Australia, New Zealand, Canada, Mexico, Chile and Peru. There’s widespread opposition to the TPP in many countries, with opponents claiming the deal will benefit big businesses and not workers. The US-led initiative is a key part of President Barack Obama's pivot to Asia, but it has proven to be a controversial issue ahead of elections in November.