Platform controller John Keeling, commercial director Matt Rennie and product director Richard Dines have all resigned from the firm, reports Paid:Content.
The website says that some of the remaining 15 staff at SeeSaw are in talks over their future with Criterion Capital Partners, which acquired a majority stake in the firm from Arqiva last month.
The resignations are another blow following a report that former Channel 4 chief executive Michael Jackson had walked away from his role as chairman designate of SeeSaw, as the online TV site struggles to secure its financial future.
It is understood that Criterion has been so far unable to lock down funding for SeeSaw from its lead backer in the investment consortium Weston Capital.
Channel 5 shows have now dropped off the site, following Channel 4's disappearance last week, meaning that SeeSaw no longer has any catch-up TV content.
The site now only offers archive shows from BBC Worldwide and some independent producers, and this lack of content risks losing its estimated 900,000 monthly unique users.
The technology underpinning SeeSaw, which Arqiva acquired from the defunct video on-demand venture Project Kangaroo, still has value and so Criterion may look to redeploy it in another market or sell it on to another company.
Arqiva, which initially announced plans in May to close SeeSaw after failing in its 16-month search to find a buyer, is to retain a 25% stake in the company under the new arrangement.