Hewlett-Packard buys Compaq Computer (2001-2002)

Why: To beat back Dell in PCs and get within striking distance of the overall IT leader, IBM.

Price: US$25 billion in stock, though the value fell to US$19 billion by the time the deal was completed nearly a year later.

Hostile/friendly: Friendly, but the move quickly turned messy as parts of HP's own board -- led by the Hewlett family -- opposed the merger, which was led by CEO Carly Fiorina.

Key premerger stats:

Revenues: HP: US$47 billion; Compaq: US$40 billion

Head count (combined): About 162,000

Number of products (combined): 85,000

HP and Compaq's PC businesses, No. 2 and No. 3, respectively, behind Dell at the time, were both losing money.

Postmerger:

Rocky for a while. HP laid off more than 15,000 employees, or 10 per cent of its workforce. Fiorina was forced out, and new CEO Mark Hurd was hired to take her place. HP later revealed that it had been spying on board members and the media. Four years later, HP has reached its fiscal goals. It reported US$104 billion in revenue last year and US$9.6 billion in net income. In 2006, HP regained the lead from Dell in PCs and took the overall IT spot from IBM. And it is hiring again: The company now has 156,000 employees, up from 145,000 immediately after the merger.

Other major HP acquisitions:

1997: VeriFone, in a US$1.2 billion stock swap (sold in 2001)

2006: Mercury Interactive, for US$4.5 billion

2007: Opsware, for US$1.6 billion