Nearly 40% of the haul came in the days after Castro's well-reviewed performance at the Miami debate, according to his campaign.
Democratic presidential candidate Julián Castro raised $2.8 million in the second quarter, according to his campaign.
Almost 40% of that money came in over the few days following Castro's well-reviewed debate performance late last month in Miami, campaign spokesman Sawyer Hackett said.
The total raised continues to place Castro, the former U.S. housing secretary and San Antonio mayor, in the back of the pack among 2020 contenders. But it is a marked improvement over his first-quarter haul, which was $1.1 million.
Castro's campaign shared the figures after he revealed some of them to reporters while campaigning in Iowa. The campaign faces an end-of-day deadline Monday to report its full second-quarter finances to the Federal Election Commission.