Back to school season failed to provide the sales boom that computer manufacturers had hoped for.
That's one takeaway from two new reports on the global PC market released Tuesday by analyst firms International Data Corporation and Gartner.
Both research firms agreed that the PC market was especially bad in the United States during the three months ending Sept. 30. Gartner said U.S. PC shipments declined 10% year-over-year to 14.7 million primarily due to "a very weak back-to-school sales season."
“Weak back-to-school sales were further evidence that traditional consumer PC demand drivers for PCs are no longer effective,” Gartner principal analyst Mika Kitagawa said in a statement.
Although Kitagawa said that sales of PC sales to businesses are "stable," a worldwide computer component shortage could affect corporate sales in the future. Hardware makers like HP Inc. and Dell Technologies risk upsetting business customers if they raise the prices of their PCs to offset the rising costs of components like flash memory.
As U.S. PC shipments tanked, Gartner said global PC shipments dropped 3.6% year-over-year to 67 million versus IDC’s estimate that worldwide PC shipments were relatively flat at 67.2 million. The results between the two analyst firms likely varied because IDC counts Chromebook laptops, which are powered by Google's Chrome OS and manufactured by third-party companies, in its numbers while Gartner does not.
Get Data Sheet, Fortune's technology newsletter.
Although the market for more expensive PCs appears to be declining, IDC notes that sales of Chromebooks appear to be picking up.
"Despite the overall contraction, Chromebooks remain a source of optimism as the category gains momentum in sectors outside education, especially in retail and financial services," IDC senior research analyst of devices and displays Neha Mahajan said in a statement.
Both research firms listed HP hpq as the world's biggest PC shipper in the third quarter, citing the company's Asia PC business as doing particularly well. Neither gave a reason.
Lenovo was the No. 2 PC shipper in the third quarter, although Gartner said that the company is "in a downward trend with declining shipments in eight of the last 10 quarters."
Dell came in third in both of the reports with relatively flat PC shipments compared to the previous year during the same quarter.