Lending volume hit BRL 64.90 billion (USD 20.62 billion) last month, up from BRL 56.75 billion (USD 18 billion) in February.
Transactions figures reached 127,680 compared to 105,389 the previous month.
B3 is the product of the merging of BM&FBovespa and Cetip, Latin America's largest depository for over-the-counter securities and derivatives, which was completed in the beginning of April.
Exchange-traded fund (ETF) transactions involving B3 totaled 277,156 in March, up from 175,896 in February.
ETF transaction value on the exchange reached BRL 3.79 billion (USD 1.2 billion) in March, compared with BRL 3.21 billion (USD 1 billion) in February.