The bleak financial climate has forced a wait-and-see policy at Twickenham as the successful host nation will need to stump up an £80million guarantee to the International Rugby Board.
"We've been doing a lot of detailed work on the numbers," said Baron.
"A decision on whether it's wise too put in a bid is finely balanced indeed.
"We should leave a no-go decision as late as possible given the recession.
"To put it bluntly, as a business what we're being asked to is make an £80million guarantee in 2009 for an event that takes place in 2015.
"That's a big ask and will be a very difficult decision to take. One or two governments are prepared to provide guarantees.
"Our own government have made it plain there won't be any guarantee."
The recession is having an effect on ticket sales for England's three home matches during this year's Six Nations Championship.
Tickets for the games against France and Scotland have gone on general sale after some were returned by clubs, a rare occurrence for the championship.
"We should still be able to sell out each match. A question mark remains over Italy - we could fall short by two or three thousand there," said Baron.
"All three matches are on public sale and we're having to work hard to achieve sell outs. Even for Six Nations matches it's difficult.
"Hospitality sales for the Six Nations will be down by 27 per cent against budget. It's entirely recession-related.
"Clubs have always taken up the entire allocation for the traditional games but we're getting returns.
Baron added: "Focusing on 2009-10, we could suffer a 10 per cent drop in revenue, a big number for a £100million-plus per year business."