The TISA is a mega-agreement currently being negotiated between 23 parties (counting the EU as one), who call themselves, ironically, the Really Good Friends of Services. The TISA talks began formally in March 2013.
Their aim is to extend the scope and rules of the General Agreement on Trade in Services (GATS) at the World Trade Organization (WTO). Attempts to achieve that goal through the Doha round have been stalled for some years. The TISA is intended as a ‘gold standard’ agreement that other countries can accede to, set new standards that will inform other agreements, and eventually be incorporated back into the GATS to apply to the whole WTO membership.
TISA is one of three mega-negotiations currently underway. The other two are the Trans-Pacific Partnership Agreement (TPPA) and the Transatlantic Trade and Investment Partnership (TTIP). The US and its industry are dominant players in all three negotiations.