Jeff Orr told iTWire: "The tally at the end of 2009 had global netbook shipments consisting of around 24 percent for all types of Linux compared to 76 percent for all versions of Windows.
"Total netbook shipments for 2009 topped 36 million units to all regions of the world."
Last year, based on shipments for the first half of 2009, ABI Research had predicted that GNU/Linux would corner about a third of global netbook share.
Orr said that the first half of 2010 was not looking good for GNU/Linux netbooks.
"Without guessing what the second half of 2010 will hold, the first half hasn't fared well for Linux-based netbooks," he said.
"Major launches of Linux (Android, Chrome OS, and MeeGo - to name three) have not materialised in netbooks. ARM-based clamshell netbooks that were expected to enter commercial availability at the close of 2009 have not been realised either.
"ABI Research predicts that Linux market share in netbooks for 2010 will at best be flat year-over-year, if not decline."
The company's figures are based on shipment details from manufacturers such as Acer, Asus, BenQ, Classmate, Dell, Fujitsu, Gigabyte, HP and Lenovo among others.
Figures are collated four times a year. ABI Research uses the term netbook to mean a newer category of personal computer, similar to a laptop computer, but smaller, more portable, and less expensive with "value" as the key selling proposition.