Utilize the input text as a context reference, choose the right relationship between David Rubenstein and Carlyle Group 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.

The private equity industry has changed the most in decades as its investor base evolves and clients demand more fee concessions, Carlyle Group LP’s David Rubenstein said.

Answer: employer