Changes to funding rate and mark price calculation September 18, 2025

Dear Flipstars,

Effective September 18, 2025, at 08:01 UTC, there will be a change in the funding fee and mark price calculation for all perpetual swaps listed in Flipster. 

The formulas will be as follows:

1. Funding Rate

   Before September 18, 2025, at 08:01 UTC:

   Funding Rate (F) = Average Premium Index (P) + clamp (interest rate per funding interval - Premium Index (P), 0.05%, -0.05%)

   After September 18, 2025, at 08:01 UTC: 

   Funding Rate (F) = [Average Premium Index (P) + clamp (interest rate - Premium Index (P), 0.05%, -0.05%) ] / (8/N), where N = funding interval

    

2. Mark Price

   Before September 18, 2025, at 08:01 UTC:  

   Mark Price = Median (Price 1, Price 2, Last Price) where Price 2 = Price Index + Moving Average (150 Seconds Basis)

   After September 18, 2025, at 08:01 UTC: 

   Mark Price = Median (Price 1, Price 2, Last Price) where Price 2 = Price Index + Moving Average (30 Seconds Basis)