NEW YORK — The owners of AMC Theatres say a $20 adult ticket price for an IMAX showing of "Shrek Forever After" at some of its theaters was posted online in error.

AMC spokesman Justin Scott said Friday that a limited number of its theaters "posted incorrect pricing." He says customers who bought a $20 ticket would be eligible for a refund.

The Wall Street Journal reported that the $20 price was posted Wednesday for weekend shows at four Manhattan theaters. By Friday, three of those theaters had tickets ranging from $17 to $19, and at the fourth, the price would be changed to $19, Scott said.

"Shrek Forever After" is the series' fourth installment, and the first in 3-D.