No authorisation required, a wholesaler can sell at what ever price they want. Too expensive they will go out of business, too cheap they will go out of business!
It's all based on competition.
A wholesaler will be able to sell lower than a competitor if they are generating a higher volume of sales, because this gives them the ability to negotiate a better buying price from the distributor/manufacturer.
It's like a retailer (you) buying wholesale, you are going to get a better price if you buy 300 of something, than you are if you are buying 25, and so on.
That's how a lot of BELOW wholesale prices end up on ebay. The wholesaler can slash his normal wholesale price if they are getting a high sales turn over there, and of course cheaper prices will usually equal more sales, so it feeds itself.
Low prices, more sales, even lower price at times because they have negotiated a better buying price = no chance for the competition because the market is locked up tight.