Nintendo's Wii U system didn't manage to outsell its predecessor during its first full sales month in the US.
Sales monitor NPD noted that Nintendo's latest system shifted about 460,000 units in December, meaning the system did not sell out despite the supply constraints.
In December 2006, Nintendo sold about 475,000 Wii units and had depleted its entire stock - something which the corporation struggled to replenish for a full year as demand intensified.
The Wii U launched across North America on November 18 and sold about 400,000 units in its first week.
Analyst group EEDAR previously predicted Nintendo would sell about 600,000 Wii U units in December.
Nintendo's marketing executive has denied that the system has underperformed.
"While the Wii launch established new benchmarks in the United States, Wii U has surpassed its predecessor in perhaps the most important category: revenue generation," said Nintendo of America sales executive Scott Moffitt.
The Wii U business made $300 million in revenue in the United States, more than the $270 million generated by the original Wii in December 2006. This is primarily due to the original Wii selling for $100 less than the basic Wii U system.
Nintendo sold the original Wii at a profit, while the Wii U is sold at a loss.
The revenue numbers suggest the original Wii has a higher games attach rate than the Wii U.
In terms of software, New Super Mario Bros. U performed best with 580,000 units sold to date.
Meanwhile, Microsoft sold 1.4 million Xbox 360s during December.