General Electric has offered 4 billion euros ($5.6 billion) to buy the property assets which Spanish bank Santander is selling to fund its bid for parts of Dutch bank ABN AMRO, newspapers reported on Friday.
A Santander spokesman said the bank had no immediate comment to make on the report.
A source familiar with the process said bidders had until Friday to make binding offers for some or all of the property and that a deal should be completed within a month.
Spain's largest bank put almost all of its Spanish property assets on the block in June and set a price tag of about 4 billion euros on the sale and leaseback deal.
At that time an official with the bank said it would make capital gains of 1.4 billion euros and would push ahead with the sale even if the ABN deal fell through.
Santander, Royal Bank of Scotland and Fortis have made a mostly cash bid for ABN that is currently worth about 70 billion euros, well above a rival bid from Barclays valued at around 59 billion euros.