The Edinburgh club had urged fans to invest in the scheme after the full extent of their financial problems was revealed earlier this month. Doubt was cast over the club's survival after a winding up order was issued over a tax bill of almost £450,000, with Hearts bosses initially fearing last weekend's game against St Mirren could be their last.
An agreement was subsequently reached with Her Majesty's Revenue and Customs to extend the deadline for payment until December 3.
A Hearts board message to fans on the club's website read: "Hearts would today like to thank every supporter who has contributed to an excellent start to the club's fundraising efforts as the club's share offer reaches the halfway mark.
"The share issue has now broken through the £600,000 mark after the first three and a half weeks and this shows the dedication and love that we all have for Heart of Midlothian Football Club.
"By selling out home matches, as you did for our game against St Mirren, the club benefits from improved income that will help us to pay players and staff.
"There is still a great deal to be done and we must keep up the good work that is happening in order to maintain our recovery plan and see us through to the end of the season."
Hearts this week revealed they had rejected a takeover offer from former Livingston owner Angelo Massone and have also turned down a bid from the Foundation of Hearts, whose aim is supporter ownership.
The message to fans continued: "Your commitment so far is all the more impressive given the stern barriers that we have had to overcome along the way, whether that is demands from tax authorities, opportunism from those interested in making a quick profit for themselves, or the self-publicists and dreamers who value themselves more than the club.
"Our message to them is step aside, we have work to do and this work is for the club and nothing but the club. Anything else is simply an unnecessary distraction."
- Sports & Recreation