Question: What number largest bank is the sponsor of the World Rugby Sevens Series?

Context articles: 2016–17 World Rugby Women's Sevens Series
World Rugby Sevens Series
2015–16 World Rugby Sevens Series
Kenya national rugby sevens team
2014–15 World Rugby Women's Sevens Series
2016–17 World Rugby Sevens Series
HSBC
Fiji national rugby sevens team
2015–16 World Rugby Women's Sevens Series
2017–18 World Rugby Sevens Series

The 2016–17 World Rugby Women's Sevens Series was the fifth edition of the World Rugby Women's Sevens Series (formerly the IRB Women's Sevens World Series), an annual series of tournaments organised by World Rugby for women's national teams in rugby sevens.
The World Rugby Sevens Series, known officially as the HSBC World Rugby Sevens Series due to sponsorship from banking group HSBC, is an annual series of international rugby sevens tournaments run by World Rugby featuring national sevens teams.
 The series, organised for the first time as the World Sevens Series in the 1999–2000 season, was formed to develop an elite-level competition series between rugby nations and develop the sevens game into a viable commercial product for World Rugby.
The 2015–16 World Rugby Sevens Series, known for sponsorship reasons as the HSBC World Rugby Sevens Series, was the 17th annual series of rugby union sevens tournaments for national men's rugby sevens teams.
 The Sevens Series has been run by World Rugby since 1999–2000.
 This season, the series expanded from nine to ten events.
The Kenya national rugby sevens team competes in the World Rugby Sevens Series, Rugby World Cup Sevens and the Commonwealth Games.
 They are currently one of the 15 "core teams" of the World Series, with a guaranteed place in all ten events each season.
 Kenya recorded its first tournament win in the World Rugby Sevens Series after beating Fiji at the 2016 Singapore Sevens.
The 2014–15 World Rugby Women's Sevens Series was the third edition of the World Rugby Women's Sevens Series (formerly the IRB Women's Sevens World Series), an annual series of tournaments organised by World Rugby for women's national teams in rugby sevens.
 The series also doubled as an Olympic qualifier for the first time ever.
The 2016–17 World Rugby Sevens Series, known for sponsorship reasons as the HSBC World Rugby Sevens Series, was the 18th annual series of rugby sevens tournaments for national rugby sevens teams.
 The Sevens Series has been run by World Rugby since 1999–2000.
 South Africa won the Series with a comfortable 28-point margin over England; South Africa won five of the ten tournaments.
HSBC Holdings PLC is a British multinational banking and financial services holding company, tracing its origin to a hong in Hong Kong.
 It is the world's seventh largest bank by total assets and the largest in Europe with total assets of US$2.374 trillion (as of December 2016).
 It was established in its present form in London in 1991 by The Hongkong and Shanghai Banking Corporation Limited to act as a new group holding company.
 The origins of the bank lie mainly in Hong Kong and to a lesser extent in Shanghai, where branches were first opened in 1865.
 The HSBC name is derived from the initials of the Hongkong and Shanghai Banking Corporation.
 The company was first formally incorporated in 1866.
 The company continues to see both the United Kingdom and Hong Kong as its "home markets".
The Fiji national rugby sevens team is one of the most popular and successful rugby sevens teams in the world.
 Fiji has won the Hong Kong Sevens a record seventeen times since its inception in 1976.
 Fiji has also won the Rugby World Cup Sevens twice — in 1997 and 2005 (coincidentally, the two times it has been held in Hong Kong).
 The South African national rugby sevens team is currently the reigning World Rugby Sevens Series Champions in World Rugby.
 Fiji is also known for winning the gold medal at the 2016 Summer Olympics in Brazil, the country's first medal in any event.
The 2015–16 World Rugby Women's Sevens Series was the fourth edition of the World Rugby Women's Sevens Series (formerly the IRB Women's Sevens World Series), an annual series of tournaments organised by World Rugby for women's national teams in rugby sevens.
 The tour was a companion to the 2015–16 World Rugby Sevens Series for men.
The 2017–18 World Rugby Sevens Series, known for sponsorship reasons as the HSBC World Rugby Sevens Series, will be the 19th annual series of rugby sevens tournaments for national men's rugby sevens teams.
 The Sevens Series has been run by World Rugby since 1999–2000.