Sources told ESPN that the deal is worth around $13 million plus an additional $2m if incentives are met. If the final payout does reach $15m that would tie the previous record signing in Major League Soccer, when Ezequiel Barco moved from Argentina's Independiente to Atlanta in 2018 for the similar amount.
Sao Paulo said on its website that the fee was a record negotiation for a player moving from South America to North America and added the club would retain 20% of the players' rights in the deal. FC Cincinnati have yet to officially announce the move.
The Cincinnati Enquirer and the Queen City Press were the first to report the details of Brenner's transfer.
Brenner, 21, would likely be classified as a Young Designated Player, meaning his cap hit will be substantially lower than it would be for a regular Designated Player, though MLS has yet to formalize the roster rules for the 2021 season.
Brenner scored 22 goals in 44 matches for Sao Paulo this season and his performances had alerted the attention of clubs across Europe, with Ajax among those interested on the forward.
The Eredivisie club instead landed Sebastien Haller from English Premier League club West Ham United -- though that was not without its difficulties, as the Dutch club made an administration error and left Haller off its roster for the Europa League by mistake.
That FC Cincinnati has managed to land Brenner amid competition from Europe's major soccer clubs is something of a coup for sporting director Gerard Nijkamp and manager Jaap Stam.
Brenner's move to MLS comes at a good time considering Sao Paulo's financial limitations under new coach Julio Casares.
Preseason training in MLS is scheduled for Feb. 22, with the league's opening matches slated for April 3.
ESPN Brasil's Gustavo Faldon contributed to this report.