If selic is below or at 8.5% the rules have in place that is would be at the current selic rate x 70% + TR.

Note that the TR is an benchmark index which is created and maintained by the Brazilian government that is calculated from an average of CDBs charged by banks. The Selic rate as per on Bloomberg - http://www.bloomberg.com/quote/BZSTSETA:IND for Selic and https://www.quandl.com/data/BCB/13421-Referential-rate-TR-to-preset-mortgages for central bank rate for TR.