The offer I made on the house I purchased was about 8% below their asking. It was bank owned and had been on and off the market for something like two years when they were trying to short sell. They accepted my offer. How long has this place you are interested in been on the market? They are more inclined to accept a lowball offer if it’s been on the market for a while. Even if they’ve reduced recently. 10% is not unreasonable. However, 10% on a higher priced property is more acceptable than, say, 10% reduction on a lower priced condo. I say it’s worth a try. But as mentioned, be prepared that if they reject it, they may not be inclined to counter or consider other offers. It can be emotional.