Opendoor, most recently valued at $3.8 billion, began firing almost 50 of its roughly 1,300 employees in June, according to people familiar with the matter. It has also asked between 200 and 300 people in offices across the country to relocate to its Phoenix location, said the people, all of whom asked not to be identified because the company is private. Those employees will have about six to nine months to decide whether to make the move or leave the company.