Is it bigger than Eurocup or Formula 1?
As for the sporting events in 2015... you guys made me LOLz at your definition of major sporting events. All the sporting events mentioned are as massive as the NBA.
The Rugby World Cup is a truly massive event, much, much bigger than the NBA. Check out the stats, from memory it is only just behind FIFA World Cup and Olympics.
It only takes place every four years so to compare to F1 would be wrong, as there seems to be one of those every month.
As for Eurocup, no idea. I guess it would depend on who is playing. But you mentioned 2015, and to say that there is no big global event would just be wrong.
Of course, here in Asia it is only really Japan and Korea, as well as Hong Kong that are any good at it.
Here are some stats from the RWC:
The tournament is one of the largest international sporting events in the world, surpassed in scale only by the FIFA World Cup, the Olympics, and the Tour de France. The first World Cup, in 1987, had a cumulative world television audience of 300 million; its successor, the 1991 event in England, reached 1.75 billion. South Africa's 1995 tournament reached 2.67 billion, and the 1999 Welsh-hosted event reached 3 billion. The 2003 tournament had a cumulative world television audience of 3.5 billion, and the final, between Australia and England, became the most watched rugby union match in the history of Australian television. The event was broadcast in 205 countries. The 2007 tournament had a cumulative world television audience of 4 billion.