The other day, I was speaking to a potential client and offered to evaluate the property and she said that she had it appraised already. I think some sellers do not understand the difference between appraised value and market value.
An appraisal is done by a licensed appraiser and they give you a value for your home based on what properties similar to it have sold. They usually look back about 6-12 months.
A market value can be given to you by a real estate agent/broker and is typically done when you are intending to sell your property or considering it. A real estate broker looks back at the same information that the appraiser did but also looks at the current listings and may even look forward as well using the direction of the current market.
The difference is that the appraised value is based on sales that took place 6-12 months so those properties might have been listed 12 to 18 month ago. The market 12 months ago most likely in Manhattan is not the same as the current market. So while an appraised value can help you for tax purposes or an estate, when selling you really want to be able to get the market value from a Manhattan real estate broker with experience in your area/building. This will enable you to most up to date information.