Hamburg investor Klaus-Michael Kuhne has said he was only willing to provide funds for the transfer of Andre Hahn if the club kept U.S. international Bobby Wood.
Wood, 24, had been linked with clubs including Leicester City, West Ham and Borussia Dortmund before signing a new contract with Hamburg until 2021 in June, reportedly doubling his annual salary to around €3 million in the process.
Speaking to Sky, local billionaire Kuhne confirmed he played a role in Hamburg's dealings this summer, despite CEO Heribert Bruchhagen claiming the 80-year-old had no say in the club's transfer policy.
"I did not give the club any more for it, but I advised them to prolong [Wood's] contract and said I'd only finance Andre Hahn if they were to keep Wood," Kuhne said.
Less than a week after Wood had signed his renewal, Hamburg signed Germany international Hahn, 27, on a four-year contract from Borussia Monchengladbach for a reported fee of €6m. Both players are represented by agent Volker Struth and his company SportsTotal.
Struth has also acted as the personal advisor for Kuhne in the past and represents Hamburg coach Markus Gisdol too.
Speaking to Der Spiegel, Kuhne said Gisdol tipped him off to "get involved" through Struth.
He said: "As a result, I knew that many other clubs were chasing Wood and Hahn. I was aware that HSV needed to act quickly. But the club was not capable of doing so, and so I acted."
Kuhne, who made his fortune as a third-party logistics provider, has been funding the club since 2010. He first held transfer rights for players, then bought HSV shares and also loaned money to the club.
He played a major role in the unsuccessful return of former Real Madrid and Tottenham midfielder Rafael van der Vaart in 2012, a transfer he described as "not that sublime" in the interview with Spiegel.
Kuhne also criticised the club's transfer policy in recent years.
"HSV are a phenomenon because the scrubs always stay," Kuhne said. "Just take [attacker Pierre-Michel] Lasogga. I don't even know if I was involved in that one. Was it really necessary to hand him a five-year deal with an annual salary of over €3m after half a season? That was hara-kiri, the flop of the century.
"Football is an expensive hobby, taking an unfortunate turn. I just allowed myself [to get involved]. All of my other business ventures are reputable."