Siegel + Gale
Siegel+Gale is a brand strategy and design company founded in 1969 by Alan Siegel and Robert Gale. David Srere and Howard Belk act as co-CEOs. Siegel+Gale is a part of the Brand Consulting Group, a division of Omnicom Group (NYSE-OMC). The firm is headquartered in New York City with offices in Los Angeles, San Francisco, London, Dubai, Shanghai, and Tokyo. It serves a wide range of corporate, non-profit, and government clients. Its corporate tagline is “Simple is smart.”   Each year, they release a study called a "The World's Simplest Brands"

Founding and ownership
Siegel+Gale was founded in 1969 by Alan Siegel, an advertising, public relations and design-trained executive, and Robert Gale, a designer. The company was first operated out of Siegel's apartment in New York City. Gale sold his share of the firm in 1974.  In 1988, the company became a wholly owned subsidiary of Saatchi & Saatchi, the global brand advertising and marketing firm. After 10 years, Siegel+Gale organized an employee buy-back of the firm in association with a venture capital firm and Fleet Bank (now owned by Bank of America, Inc.).  In 2003, the firm was acquired by the large marketing and communications company, Omnicom Group Inc.

References 

International management consulting firms
Management consulting firms of the United States
Consulting firms established in 1969
Branding companies of the United States
Companies based in New York City
1988 mergers and acquisitions
1998 mergers and acquisitions
2003 mergers and acquisitions