3808. When are trades or businesses under common control?Nuco Employeercline202014-08-17T15:15:00Z2014-08-17T15:15:00Z194537Summit Business Media4163014Site Map/Retirement Plans/Pension And Profit Sharing/Qualification/Employees and Employerscontrolled group parent-subsidiary brother-sister combined group2005-01-25T00:00:00ZTaxFactsDefaultArticle116410360-00-tf1.xml362.00;#2248;#0x010100C568DB52D9D0A14D9B2FDCC96666E9F2007948130EC3DB064584E219954237AF3900242457EFB8B24247815D688C526CD44D009C4E67E972694125ABDA91AC61F5E51FTax Facts 1What is a “controlled group” of corporations? When are trades or businesses under “common control”?127700.000000000TaxFactsDefaultArticle2010-01-15T00:58:28ZSBMEDIA\moss-admin3808. When are trades or businesses under common control?Under the regulations, trades or businesses are under common control if they constitute a parent-subsidiary group of trades or businesses, a brother-sister group of trades or businesses, or a combined group of trades or businesses. The existence of these groups is determined under rules similar to those discussed in Q 3807 for controlled groups of corporations. “Trades or businesses” include sole proprietorships, partnerships, estates, trusts, and corporations.IRC Sec. 414(c); Treas. Regs. §§1.414(c)-1, 1.414(c)-2, 1.414(c)-3, 1.414(c)-4.