One of the most powerful psychological levers to influence the other party is anchoring! 

Anchoring in negotiation consists of setting a first price as a reference point throughout the negotiation process.

First, some vocabulary.

In negotiation, the ZOPA is the Zone Of Possible Agreement. It is reliant on an inherent level of uncertainty in a negotiation. Neither side quite knows where the ZOPA begins or ends, though they have their ideas. By anchoring first, you can “stake claim” on approximately where the ZOPA sits. Even if this differs greatly from your opponent’s assumed ZOPA, your moving first will cause them to reassess their own assumptions and data.

It is, in essence, a lesson in the power of random numbers, and it is reliant on uncertainty. Especially when you have limited information about the market, the first number mentioned in a negotiation has a great impact on the final outcome. This human tendency to rely too much on the first piece of information was discovered by Nobel laureate Daniel Kahneman and tested in multiple researches in negotiation, in particular by Dan Ariely. The first number mentioned in a negotiation influence people’s perceptions about what constitutes a fair price.
How can you defend against anchors? Well, be the first to anchor! Prepare with plenty of research and data on your topic so you have a logical, objective sense of the appropriate ZOPA. And, if the other side anchors first, change the metric in question (for example, by which method a business is valued—P/E, Enterprise Value, etc.).

Using anchors effectively requires some subtlety. Be aggressive, but not too aggressive as to completely derail negotiations. Or, consider meta-anchoring, which shapes the ZOPA by changing the conception of the nature of the problem (similar to framing), without mentioning a specific price.