Small is big these days for computer makers. HP Inc. hopes to prove the point this week.
The personal computer and printer portion of the now-divided Hewlett-Packard Co. is expected to unveil what may be the thinnest laptop on the market, hoping to grab greater share of a premium category that has been healthier than some other segments of the shrinking PC industry.
HP isn't disclosing details until Tuesday. But Chief Executive Dion Weisler has made it clear he is determined to burnish the company's reputation as a trendsetter in style and technology—attributes long associated with Apple Inc.
"For years, Apple has been seen as the innovator and the driver of innovation," said Ron Coughlin, president of HP's personal systems group. "HP is really taking over that mantle."
An Apple spokesman declined to comment. But HP's claim isn't likely to go uncontested, as PC makers try new designs to counteract tepid customer demand. Market researchers at International Data Corp. in January reported that world-wide PC shipments declined 10.4% in 2015, with growth registered by few major vendors besides Apple.
Some new offerings bear attributes of both tablets and laptops such as Microsoft Corp.'s Surface Pro and Lenovo Group Ltd.'s Yoga. Others, including Dell Inc., have stressed features such as beefed up encryption to appeal to corporate users.
HP is one of several laptop makers touting reduced size and weight for clamshell models as a selling point, particularly for models priced at $1,000 and higher. Apple has set a standard for sleekness since the 2008 introduction of MacBook Air, followed up with thinner versions of its MacBook Pro. I ts 12-inch model introduced in March 2015, dubbed simply the MacBook, measures 13.1 millimeters at its thickest point and 3.5 millimeters near the edges.
Rivals used the Consumer Electronics Show in January to introduce slimmer models based on the latest set of microprocessor chips from Intel Corp. Dell, for example, introduced a new 13-inch Latitude model for commercial users that is 14.3 millimeters at its thickest point.
Raza Haider, executive director for Dell's Latitude & OptiPlex products, said the trend reflects an increasing need to satisfy the tastes of rank-and-file workers—not only the technology managers who typically make PC buying decisions. So corporate PC users "no longer have to pay an ugly tax," he said.
He predicted that Dell won't lag in introducing thinner and lighter laptops, while arguing that other factors may wind up being more important to users than new claims about dimensions. "We are kind of at a point where it's a little bit of millimeter madness," Mr. Haider said.
HP is particularly motivated to create a stronger image for innovation. It inherited mature businesses that have been growing at a slower pace than operations of Hewlett Packard Enterprise Co., the other company created in the breakup completed late last year.
The company reported that revenue fell 12% in the fiscal quarter ended in January from the year-earlier period. IDC reported that unit sales in 2015 fell 5.9% for the company—No. 2 behind Lenovo—though HP boosted its share of global shipments in 2015 to 19.4% from 18.4%.
HP has already introduced some eye-catching products, including a big-screen smartphone called the Elite X3 that can be paired with accessories to be used like a PC. New products introduced in January at the annual Consumer Electronics Show included a 12.5-inch EliteBook Folio notebook measured at 12.5 millimeters thick.
HP's forthcoming laptop is expected to be even thinne r. It is slated to be unveiled at an event Tuesday in Versailles, France, organized by the New York Times.
Stephen Baker, an analyst at NPD Group who tracks retail PC sales in the U.S., said the strategy makes some sense as demand has been stronger for premium laptops than some other segments. The trouble, he said, is that such systems account for a relatively small share of the total market for portables.
"The challenge for doing really, really thin and light products is it's a very, very thin and light segment to go after," Mr. Baker said.
Write to Don Clark at don.clark@wsj.com
