HP has stretched its lead in global PC sales as rivals challenged Dell on pricing and capitalised on smarter designs and marketing nous. Dell was just the market leader for 2006 although the numbers were almost too close to call.

According to both IDC and Gartner analysis, HP had another strong period in the fourth calendar quarter of 2006, strengthening its grip on the number-one position it assumed from Dell in the second half of last year.

IDC said worldwide PC shipments grew 8.7 percent in the quarter compared to the year-ago period, despite slowing sales to businesses. Both analysts said price erosion was a significant trend in the last part of the year while Windows Vista appeared to have little effect.

By IDC numbers, HP now has 18.1 percent of the worldwide market compared to Dell’s 14.7 percent, and the rivals have swapped rankings since this time last year.

“It looks like HP has kept its momentum from the third quarter of 2006 through Q4 and has made gains in the corporate sector,” said Michael Larner, IDC senior research analyst. “HP redesigned its laptops early in 2006 and has been very aggressive on pricing. It has come out of a period [after the 2002 acquisition of Compaq] when it was quite internally focused and now has a better story to tell.”

Larner said HP’s ‘The Computer Is Personal Again’ campaign had been successful while Dell had been hurt in the fourth quarter by its dependence on business for the bulk of its sales.

However, for all of 2006, Dell just remains the PC volume leader ahead of HP, Lenovo, Acer and Toshiba, IDC and Gartner agreed. Dell edged out HP by just 0.1 percent market share, according to IDC, and by an even smaller difference, according to Gartner’s preliminary numbers.