Can someone explain the logic around why exchanges and brokers quote all their fees per share instead of per dollar? The cost to the exchange for trading 10,000 shares of a $1 stock must be about the same as trading 100 shares of a $100 stock. Yet the fees charged to the retail customer (I'm not including PFOF in this discussion) can vary from a few cents to over $100. A significant input into the fee you pay is whether your order added liquidity and the associated rebates, so let's keep the discussion only on orders that remove liquidity.
Fee per share pricing goes back to the old fixed commission pricing of the NYSE that set the commission per 100 shares. What fees add up to over $100 for 10,000 shares of a $1 stock?
Seems I've paid that when taking liquidity near the 1st of the month before hitting the next commission tier. Maybe I was taking a bigger position. Point is that the trade costs vary so widely.