Should shareholders vote against the issue, the Belgian-Dutch bank could also place shares with a friendly investor, according to a report in Dutch financial daily Het Financieele Dagblad.
Fortis, which forms part of a consortium bidding for the Dutch bank, will know the outcome of the vote on its proposed $17.82 billion share issue today.
Approval for the deal hinges on meetings in Utrecht and Brussels, in which Fortis needs the backing of 50 per cent of the shares represented for the purchase of ABN Amro.
Meanwhile, the approval of 75 per cent of attendees will be required for the share issue.
The Royal Bank of Scotland-led consortium has tabled a bid of $97 billion for ABN Amro.
Barclays Bank, with whom the consortium is vying for the Dutch company, has today formally launched its rival bid of $89 billion.