In my limited buying experience (after four boats, currently selling/shopping again), I'd say most boats listed on yachtworld.com sell for 10-15% below the last listed price (many reduced prices going on right now). Others may sell for less.
Prospective buyers who know a good price on a currently listed boat, based upon current market values, may offer close to list - others may offer a lowball number.
Keep in mind that a safety factor exists when the buyer's surveyor reveals devaluing deficiencies in his report - providing motivation for the buyer to reduce the seller's previously accepted price, and incentive for the seller to accept or counter. Negotiations can get very interesting.
True Blue . . .
sold the Nauticat