Mobile defense is a diversification or defensive strategy embraced by companies when current segment operations are likely to take a hit in the near future. Companies take a “prevention is better than cure” approach and create a buffer for possible losses going forward. A cigarette manufacturing company entering dairy business sensing an impending government ban on cigarettes is a form of mobile defense.
This expansion could be in a related or non-related industry. For example, a car tyre manufacturer may start manufacturing car batteries if the company senses saturation and dwindling sales in the tyre industry. This is expanding business into related territories. An unrelated expansion, for instance, is a pen manufacturer entering the beer industry.