Joint ventures and strategic alliances allow companies with complementary skills to benefit from one another's strengths. They are common in technology, manufacturing and commercial real estate development, and whenever a company wants to expand its sales or operations into a foreign country. In a joint venture, the companies start and invest in a new company that's jointly owned by both of the parent companies. A strategic alliance is a legal agreement between two or more companies to share access to their technology, trademarks or other assets. A strategic alliance does not create a new company.