Steve Ballmer's 4% Microsoft stake has experienced significant losses despite being his most important financial holding since joining the company in 1980.

Steve Ballmer joined Microsoft as the 30th employee in 1980 and served as CEO from 2000 to 2014, succeeding Bill Gates

Ballmer's decision to hold onto his Microsoft shares is described as the most important financial decision of his life

He currently owns 4% of Microsoft, making him a major shareholder in the company

Recent market conditions have cost Ballmer billions of dollars in unrealized losses on his Microsoft holdings