Held in Indian Wells, which tennis tournament is often called the fifth major?

It is most often called the Indian Wells Open however, BNP Paribas out of France has owned the rights to the tournament since 2009 so technically it is called the BNP Paribas Tournament. The Williams sisters boycotted the tournament from 2001 to 2014 due to allegations of the women fixing their matches which the family denies. The amount of hostility the family faced caused them to boycott the event for 13 years.

https://en.wikipedia.org/wiki/Indian_Wells_Open