Apple and Google have created an unofficial agreement not to compete for each other’s employees. Supposedly no formal written agreement exists for the deal.

The Justice Department has looked into whether companies such as Apple and Google have violated antitrust laws by arranged the recruitment of each other’s workers.

Human capital is a prime resource for tech companies–perhaps the most important resource tech companies possess. That is why Microsoft sued Google in 2005 after it hired Kai-Fu Lee away from Microsoft.