Four firms dominate IT consultancy: IBM, Accenture, EDS and Cap Gemini. They are often referred to as the 'Global Giants' [...] have high-end IT consulting capabilities but also offer various other services. Of the four, IBM is by far the largest, dwarfing the other three firms. For example, IBM's total revenues are nearly $100 billion and it employs nearly 500,000 people. In contract, both EDS and Accenture have revenues closer to $20 billion and employ roughly 150,000 people. Cap Gemini has revenues of approximately $10 billion and has a workforce of just over 120,000. [...]

IBM has the longest history per se, and is also the most embedded in the IT industry. Many still perceive IBM as a computer hardware manufacturing company. However, by the mid-1990s IBM had already started a major corporate restructuring process, shifting its core focus from computer manufacturing to software services. In 2002 it acquired PwC Consulting to further its consultancy capabilities. But the seismic shift was finally completed in 2005 with the sale of its computer manufacturing line to the Chinese firm Lenovo.

[...] EDS was never a computer manufacturer. It was established in 1962 as a data processing firm [...] In 2008 it was acquired by the computer manufacturing behemoth HP and renamed HP Enterprise Services. [...]

Cap Gemini was founded in 1967 [...] acquiring Ernsy and Young Consulting in 2002.

Accenture started as a small data processing division within Arthur Anderson, the global accountancy group. [...]

[...] two distinct types of service. First, they provide software services across all tiers of the industry. Second, they provide business services, which essentially means management consultancy. IBM and EDS arguably have the great strengths in software services, while Cap Gemini and Accenture are more formidable in management consultancy.

A special trend has bee the evolution of the integrated services model from the late-1990s onward, whereby software services firms provided services across tiers, from highest-end IT consulting to low-end IT outsourcing. The integrated services model was pioneered by the most successful Indian software firms - the Majors - who capitalised on their rapid growth via remote delivery of IT outsourcing and basic IT services to diversify up the value chain into higher-end software services. This was primarily via the acquisition of small Western business and/or technology consulting firms. Given the intra-firm efficiencies generated by the provision of integrated services, it was soon copied by the Global Giants. [...]

The first fillip to the industry occurred in the 1960s, following the decision to unbundle software and hardware by the dominant computer manufacturer IBM