Its not a Company thing but an ICAO (PANS OPS 8168) thing and therefore its a requirement.
When carrying out a missed approach follow the published missed approach procedure.
The MAP will require a gross climb gradient of 3.3% which is 2.5% net. The a/c Approach Climb Limit should ensure the aircraft can maintain a 2.5% net gradient in the event of a single engined go-around.