The difference between MSRP and the wholesale price is the RETAILER'S profit and has nothing to do with the wholesaler. The wholesaler's profit is included in his wholesale price.
So say a jewelry maker wholesales her necklace to a retailer for $50 and the MSRP is $100. The jewelry maker's costs are $10. She makes $40 'profit' and the retailer makes $50. Of course the retailer can have sales or can raise the price, whatever he deems necessary. The manufacturer and wholesale distributor can be the same or different companies. The manufacturer would set the price for a bulk sale to a distributor, his profit included in there. From there, the wholesaler can sell for whatever he wants to. Does that answer your question?
Generally, retailers expect to be able to mark up the product 50%. It depends on a bunch of things though. There's no set amount.