Apple's iPhone shipments jumped nearly 15 percent in the first quarter over the previous one, despite a slight downturn industrywide, according to new data.

Market researcher IHS iSuppli reported that Apple shipped 18.6 million of its smartphones in the first quarter, up from 16.2 million in the fourth quarter of 2010. That 14.9 percent increase marked the highest growth rate among the top five global smartphone vendors. It also stood out against an 1.5 percent sequential drop in smartphone shipments industrywide in the first quarter, which is usually a slow retail season but one that hasn't previously impacted the thriving smartphone market.

The first quarter was good to Apple thanks in part to the debut of the Verizon iPhone, iHS iSuppli noted.

"Not only did this allow Apple to expand its target market and boost shipments, it also placed additional pressure on rival smart phone brands--including Motorola, Samsung, LG and HTC--that focus on Verizon Wireless as a major customer," Tina Teng, IHS senior analyst for wireless communications, said yesterday in a statement.

Though still the No. 2 smartphone maker, Apple's latest surge in market share is inching it closer to No. 1 Nokia, which saw its first-quarter shipments drop by 14.5 percent to 24.2 million. With the ongoing shift, Apple's smartphone shipments now trail those of Nokia by just 5.7 percentage points, according to IHS iSuppli, compared with 12.2 points in the previous quarter.

Nokia's deal with Microsoft to switch its smartphone platform to Windows Phone 7 is actually hampering Nokia's shipments over the short term, according to IHS iSuppli, because consumers apparently are reluctant to buy devices based on the Symbian and MeeGo operating systems. The market researcher said it doesn't expect the deal to yield any new products for at least another year.

BlackBerry maker Research In Motion held its No. 3 spot by doing better than the overall industry, shipping 14.8 million phones, a sequential gain of 4.2 percent.

Among the Android vendors, No. 7 LG's shipments grew 60 percent, reaching 4 million during the quarter, up from 2.5 million the previous quarter.

2011's initial quarter marked the first sequential decline in smartphone shipments since the start of 2009, but IHS iSuppli doesn't see this as a long-term trend.

"The reduction of shipments reflects inventory control efforts in the smartphone market, rather than weakening consumer demand," Teng said. "This decline does not change the IHS iSuppli forecast of 60 percent growth in worldwide smartphone shipments for the entire year of 2011."