Following the 2008 financial crisis, the industry has increased its focus on reducing risk, achieving greater transparency, and improving efficiency in order to establish a safer market environment. The crisis led to a host of regulations and initiatives impacting markets, products, and participants.

Shortening the settlement cycle, while not a regulatory mandate in the United States, is an industry effort that is expected to yield important benefits including reduced counterparty risk, decreased clearing capital requirements, reduced pro-cyclical margin and liquidity demands, and increased global settlement harmonization. Major markets across the globe either are examining a move to a two-day settlement period (T+2) (Canada and Japan), are currently moving to T+2 (Australia), or have already completed a move to T+2 (European Union, Hong Kong, and South Korea).

http://www.ust2.com/pdfs/ssc.pdf