David Gold and David Sullivan have increased their stake in West Ham United to 60 per cent.
Gold and Sullivan, who took charge at Upton Park in January when they acquired a controlling 51 per cent stake from CB Holdings, have now upped their interest following the successful battle to avoid relegation from the Premier League.
The former Birmingham City owners have each purchased an additional five per cent of the club's shares in a joint £8million deal.
They also have the option to purchase the remaining 40 per cent from CB Holdings at some point in the future.
"Myself and David Gold are, like you, West Ham United fans and our aim is to ensure our club enjoys a stable and successful future," Sullivan told the club's official website.
"To this end, we have both invested a further £4million to increase our shareholding to 30 per cent each.
"We have a long-term intention of increasing our shareholding, while we have also invited professional investors to share in our vision for this special club. Also, in the near future we hope to extend to supporters the opportunity to invest in the club.
"We are committed to putting West Ham on a firm financial footing that will form the basis, we hope, for success both on and off the pitch."