No. Brands cannot reduce the commission you already locked in.
However, If a brand updates the TAP commission during the campaign, the change only applies to creators who add the link after the update.
Your rate stays the same until the TAP campaign ends.
How it works
Here is how your locked-in rate works:
When you add a TAP link, the commission you see at that moment becomes your locked-in rate for the entire TAP campaign.
Brands can update TAP commissions during the campaign, but TikTok applies those changes only to creators who add the link after the update.
Your existing videos and commission rate remain unchanged unless you remove the link and re-add it after the brand’s update.
When can your commissions change?
Your commission can only change if:
The TAP campaign ends
The brand ends the campaign early
TikTok restricts or delists the product
You remove the TAP link and re-add it after the brand changed the rate
After the campaign ends, TikTok returns the product to normal open-collab rules, and future conversions may use different commission rates.
Summary
A brand can update the TAP commission at any time, but this never reduces the rate you already locked in.
Your TAP rate is secured from the moment you add the link and only changes once the campaign ends. Or if you re-add the link after a brand update.