I hear talk of "the WT is under financial strain." I don't know about all that. For steady income they have:
1. Kingdom Hall Insurance program.
2. Kingdom Hall Building Fund. (Donations from congregations lent back out on interest for KHall builds. WT = the bank.)
3. Weekly Circuit Assembly donations.
4. District Convention donations.
5. Contribution boxes for the Worldwide Work.
6. Traveling brothers insurance assistance program. (An amount assessed to each congregation per publisher each year.)
7. Traveling brothers automoblie assistance program. (An amount assessed to each congregation per publisher each year.)
8. Real estate sales.
9. Financial markets investments.