Creams are made by pre-mixing all the materials forming the fat-phase, that is, the emulsifier, consistency agent (Cocoa or Shea butter) and vegetable oils. (Pacific Institute of Aromatherapy)

Any personal care product that contains both water based and oil based ingredients must also contain an emulsifier. It is the emulsifier that enables these two normally repellent ingredients to mix together to form a cream or lotion. (Green People)

The reason the fat does not float to the top immediately is due to the presence of emulsifiers; in this case, a milk protein called sodium caseinate as well as several phopholipids. (Cosmetic Chemistry)