What it is:
A golden hello is slang for a signing bonus.
How it works/Example:
For example, let's assume that John works for Company XYZ. Company ABC really wants to hire him, too, but John is happy at Company XYZ and is paid well there. Company ABC offers John a job, and in order to entice him to take the offer, they offer him a $20,000 golden hello on top of his salary and other benefits. On John's first day of work at Company ABC, he receives a check for $20,000.
Why it matters:
The purpose of a golden hello is to entice talent to join a company. Typically they are only offered to high-ranking executives or employees with extremely specialized skills. From an economic perspective, companies only offer golden hellos when the fiscal benefits of doing so exceed the costs.