Skateboarding shoe and outdoor apparel maker VF Corp. said data pertaining to 35.5 million customers appears to have been stolen in a recent data breach.

The Colorado maker of apparel and footwear brands including Vans, Supreme, The North Face and Timberland told investors Thursday that its data breach estimate is based on a “preliminary analysis.”

VF said its “investigation and remediation efforts remain ongoing” following unauthorized access to its systems the company first detected on Dec. 13.