Ratcliffe, a life-long United fan and founder of chemicals producer INEOS, put in a bid for the club in February.
United's current owners, the Glazer family, began looking at options for the record 20-time English champions, including new investment or a potential sale, in November, 17 years after they bought the club for 790 million pounds as part of a highly leveraged deal.
Any sale of United would likely exceed the biggest sports deal so far - the $5.2 billion including debt and investments paid for Chelsea, sources have told Reuters previously.
In an interview with the Wall Street Journal, Ratcliffe described the club as a "community asset" rather than a financial one.
"How do you decide the price of a painting? How do you decide the price of a house? It's not related to how much it cost to build or how much it cost to paint," Ratcliffe said.
"What you don't want to do is pay stupid prices for things because then you regret it subsequently."
According to a Sky Sports report, United are set to receive more than five bids before Wednesday's deadline for second offers.
