Hutt Endorsement is a technology that can be researched at the Spaceport in Tech Level 2. It costs 150 Food and 50 Nova, and lowers the tribute fee from 30% to 20%. It is a requirement for Galactic Banking.
If the player sends a lot of resources to their ally, this technology should be researched early, as it will quickly pay for itself.
"This Tech Level 2 Spaceport upgrade nominally reduces the tribute fee to other civilisations."