Earlier this week, Citi Research said sales of the phones are expected to fall short. Citi cited thinner lines and quicker shipping times as evidence that demand for the new devices might not be as high as in earlier years.
Kuo said bearish reports are "overdone," according to blog MacRumors.
"We previously estimated the production weighting of new 2017 iPhone models at roughly 50% iPhone X and 50% iPhone 8/ 8 Plus," Kuo said. "This matches what we believe is Apple's (US) estimate for demand. At first glance, the combined first-week adoption rate for the iPhone 8/ 8 Plus might appear low (about half that of iPhone 6s/ 6s Plus and 7/ 7 Plus). However, this is due to the fact that the iPhone X is not included, not because iPhone 8/ 8 Plus first weekend sales have been weak."
Citi suggested that sales will be lower during the fiscal fourth quarter as customers wait for the iPhone X to release in November before making a purchase decision.