Analyze the relationship between 'Worldpay' and 'Bain Capital' within the context of the input sentence.
Options: currency, employer, chairperson, parent organization

Headquartered in London, Worldpay was carved out of RBS (LSE: RBS.L - news ) five years ago and established as a standalone business by private equity firms Advent International and Bain Capital - who paid £1.7bn for the business.
parent organization