"Everything was arranged for this to happen but I didn't do the deal because we already have quite a few races in that part of the world and I thought it might be a little bit over the top to have another one."
According to the Independent, Vietnamese organisers were willing to pay approximately $570 million to secure a grand prix every year for 10 years. On average, hosts pay approximately $44 million a year for the right to hold races.
But keen to maintain a balance between honouring F1's past and breaking new ground, Ecclestone was wary about committing to a new grand prix when he had already copped backlash for introducing races in places like Azerbaijan and Russia.
"It (Vietnam) hasn't got any racing history at all," Ecclestone said. "So I didn't want to put another race in the same sort of area where we already have very good promoters.
"And I was criticised for putting the races in Baku and in Russia because they hadn't got that much racing history."
Liberty Media CEO Greg Maffei last month criticised Ecclestone for caring only about dollars rather than strengthening the F1 brand. But the Brit's revelation he rejected Vietnam's approach because he felt it wasn't the right move for the sport, even if it made sense financially, suggests perhaps this wasn't always the case.
"It's our job to do far more to help the promoters be successful. Bernie's attitude was, 'How much can I extract from them, how much up front?' I heard him call them the victims," Maffei said.
"So we ended up with races like Baku in Azerbaijan where they paid us a big race free but (the organiser) does nothing to build the long term brand and help the business.
"Our job is to have partners who pay us well but who also help us build the product. But it's incumbent upon us to bring best practice."
It's not the first time Vietnam's bid to be part of the F1 community has been smacked down. The nation put its hand up in 2010 when plans were made to build a track in Ho Chi Minh City, but the process hit too many snags.
Vietnam reportedly opened its first racetrack in 2016 but it is not up to F1 standard.