There is one supplier is SaleHoo who distributes Under Armour products -
Link hidden: Login to view I suggest visiting their site and making an inquiry.
I have previously made contact with Under Armour through live chat and email. The representative I had a chat with suggested calling their independent sales team at 1-888-828-1547 for wholesale inquiries.
Below's the link to the email I received in response to the wholesale/reseller inquiry I sent -
Link hidden: Login to view
Hope this helps :)