The council-run campaign hopes to raise Â£428,659 to restore three of the 154 Victorian arches, and demonstrate to potential funders that the restoration has popular local support to attract external funding.
Brighton Marina developers Brunswick Developments pledged Â£25,000 after directors agreed unanimously to back the project at their latest board meeting.
The total raised so far stands at Â£261,513 with 1422 backers. The campaign runs until November 30.
Andrew Goodall, Brunswick Developments' managing director, said: “Brighton’s seafront is its shopfront, whatever we can do to maximise its potential will have benefits for residents, tourists and the economy.
“Along with 1,500 other stakeholders in the city and beyond who have already pledged to the campaign, the Brunswick directors are also keen to see them restored.
“The terraces are the Marina’s neighbour, and so of course we want to see them do well, look great and become full of activity. We have been impressed by the thoughtful regeneration of the seafront to the west of the city and are now committed to supporting further regeneration to the east.”
Howard Barden, VisitBrighton head, said: "This pledge is brilliant news and brings a significant boost to the fund as we go into the final weeks of the campaign. With more pledges like this we can do it! City wide support has been tremendous and demonstrates how keen so many people are to see our seafront terraces restored to their former glory.
“We’re now 60 per cent of the way towards reaching our target and I want to thank everyone for helping us come this far. As we approach the home straight, these bigger business pledges are going to be instrumental in getting to the target on time so I would urge all businesses that haven’t already contributed to come forward as soon as possible.”
The terraces along Madeira Drive have been closed to the public since 2013 because of structural concerns, but the Victorian landmark was once a thriving section of the seafront’s promenade.
Visiting the city for the Veteran Car Run at the weekend, Chris Evans and Damon Hill were the latest in a string of well-known faces to add their support for the campaign.
Residents have also set up a raffle and auction to raise cash for the project, with the winners drawn on November 24 at The Cricketers, Black Lion Street.
There are more than 350 prizes donated by local businesses, and tickets are being sold at 40 outlets in the city. To find out more search Save Madeira Terraces Grand Raffle Draw on Facebook.
To donate to the crowdfunding campaign, visit: spacehive.com/madeira-terrace