A huge exodus from San Francisco may be under way as high-tech companies pack their bags for cheaper North American cities and regions, according to a study.

San Francisco is the most expensive North American city for a high-tech company do to business, with an estimated average cost of $43 million a year, according to The Boyd Company, a consulting firm that advises major companies on location planning. For example, a company relocating to Baltimore from San Francisco would see a savings of about 21 percent, according to the study’s figures.