Members of the Dons Trust, the fan group who own the League One club, created the bond earlier this month to help raise funds for the side’s move back to Plough Lane.
Wimbledon have an £11m shortfall to make up to move into their new 9,000-seat stadium for the start of next season and the bond is helping to reduce that.
So far it has raised over £5m and it was originally due to close on February 14, but given its success it will remain open until the end of the season.
Organisers are now hoping it can raise a further £2.5m, meaning Wimbledon will only need to borrow £3.5m from a commercial lender.
Bond spokesperson Charlie Talbot said: “Passing one key milestone is great and shows just what the community spirit of this fanbase can achieve working with the club and the Trust.
“But we can’t let up. We need to keep pushing on and aim at a new target.
“The more the bond raises the more we change the game and control our own destiny both for funding the stadium construction, and improving our playing and operational budgets when we go home.
“Let’s aim for £7.5m now and see how quickly we can get there.”
Investment terms remain the same at a minimum investment of £1,000 over five, 10 or 20 years with a chosen interest rate between zero and four per cent.