You have not yet exchanged contracts, but the buyer will not boost the price. Your estate agent swears there are no better offers. He also dismisses as irrelevant the fact that the buyer has offered him a palatial room in his own house complete with panoramic views.
One million members of the Birmingham Midshires building society now find themselves in a situation closely parallel to this. Last August, the board of Birmingham Midshires (not, of course, to be compared to an estate agent) announced an offer for the society from the Royal Bank of Scotland.
Birmingham Midshires agreed a price range of pounds 605m to pounds 630m. Shared evenly between members, this dangled the prospect of a windfall for every member worth pounds 600 each. Fine.
Now, in the past eight months, prices for this particular type of property have very nearly doubled. Converted building societies such as Northern Rock and Halifax are valued by the stock market at least 20 times their annual earnings.
Birmingham Midshires is being sold at just 12.5 times its annual earnings. If it were sold at a price closer to the market consensus, its policyholders could expect windfalls of more than pounds 1,000 each.
If Royal Bank succeeds, it will be snapping up the society at a bargain price.
However, Mike Jackson, chief executive of Birmingham Midshires, says the City is over-valuing other converted societies. In other words, it is not a fair comparison.
Mr Jackson, who will be offered an executive director's job at the Royal Bank if the deal goes through, may have a point. City prices for banks have entered the stratosphere in the last eight months and analysts agree that most are overpriced.
But if the prices of building societies had sunk instead of risen, would Royal Bank have stuck so doggedly to its original offer?
To extend the analogy, contracts are still to be exchanged. Policyholders are still the owners of Birmingham Midshires. They have the right to veto any deal, whether recommended or not, by the board of directors.
In April, the exact nature of that deal will become clear when Birmingham Midshires reveals exactly how it plans to share out the proceeds of a sale. Policyholders are likely to have a chance to vote on it before the end of July.
A group of dissident members are trying to bring the directors of Midshires to account under the banner of Save Our Building Societies. If they can muster enough support, they may be able to change the price of the deal - or even call it off altogether. After all, the board is there to look after the interests of policyholders. Not directors.
Bob Goodall, co-ordinator of Save Our Building Societies, can be contacted on 01727 847370.