Utilize the input text as a context reference, choose the right relationship between Steve Ballmer and Microsoft from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

(Reuters) - Former Microsoft Corp Chief Executive Steve Ballmer owns a 4 percent stake in Twitter Inc, Bloomberg reported, citing an email from him.
owner_of