The organization of the International Bible Students Association was incorporated on 30 June 1914 and the governing document was amended by special resolution in 1949, 1951, 1958, 2005, 2014 and 2016.
In the Watchtower of December 15, 1914, Russell wrote (p.371)
For the sake of our many new readers we explain the the Watch Tower, Bible and Tract Society, as the parent organization, represents all the activities in Christian work with which THE WATCH TOWER and its editor are associated. All the work done through the International Bible Students Association and Peoples Pulpit Association, directly and indirectly, is the work of the Watch Tower, Bible and Tract Society.
It was registered as a charity in the UK on 18 November 1964. The charity spends its money to "provide serviced facilities to support religious activity of Jehovah's Witnesses. Arrange for venues to host conventions for Bible education. Pay expenses for and take care of living arrangements for members of the Worldwide Order of Special Full-Time Servants of Jehovah's Witnesses."
The current trustees are Michael Simpson, Andrew Paul Sutton, Stephen Charles Hale Symonds, Jonathan Manley and Karl William Snaith.