Biden and Kerry may have been receiving payouts for corrupt foreign deals via their sons' fund, Rosemont Capital.
Senator John Heinz (ketchup fortune) died in a plane crash and John Kerry ended up marrying his wife. His stepson in Chris Heinz, who partnered with Biden's son Hunter, and their friend Devon Archer to create Rosemont Capital.
The partners attached several branches to the Rosemont Capital trunk, including Rosemont Seneca Partners, LLC, Rosemont Seneca Technology Partners, and Rosemont Realty.
It seems that soon after a deal is made between Kerry or Biden with foreign countries/companies, their sons' fund soon receives a deal with the same entities.
"Rosemont Seneca Partners had been negotiating an exclusive deal with Chinese officials, which they signed approximately 10 days after Hunter visited China with his father. The most powerful financial institution in China, the government’s Bank of China, was setting up a joint venture with Rosemont Seneca."
https://nypost.com/2018/03/15/inside-the-shady-private-equity-firm-run-by-kerry-and-bidens-kids/