Former governor and Senator Bob Graham has written another big check for his daughter's campaign, this time pouring $500,000 into the final stretch of the primary race.

His Aug. 17 contribution makes him one of her biggest donors, having given more than $1 million since May of last year, according to her PAC's records.

Gwen Graham hasn't been shy about tapping her family's wealth, with her Washington Post-linked relatives also chipping in six figures to her campaign.

Like his daughter, Bob Graham's greatest source of wealth is in the family company, the Graham Companies – or at least it was during his last financial disclosure, in 2004, when the outgoing senator's report showed a net worth of between $5 million and $25 million.

Although she's not been involved in the family company since she was elected to Congress in 2014, the Graham Companies' involvement in a controversial mega-mall project has been used against her this primary.