I realise this is probably common knowledge for some people, however I keep losing this list whenever I need it. So, this entry is more a personal archive so that I can always access this, and if someone else finds it valuable, so be it.

Top reasons companies outsource (in order):

Reduce Operating Costs
Focus on Core Competencies
Create a Variable Cost Structure
Access Needed Skills
Increase Speed to Market
Improve Quality
Conserve Capital
Grow Revenues
Foster Innovation