A tax levied on buyers means that the buyers will have to pay more, which causes their demand to fall. The fall in demand also hurts sellers, by forcing them to reduce their sale price. Similarly, a tax levied on sellers is like a cost of production increase, and sellers have to pass along a portion of that cost increase to buyers in the form of higher prices. So the effects of taxation on Prices, on quantity and on tax incidence are the same whether the tax is imposed on buyers or sellers. Finally, the tax also reduces the market size by reducing the equilibrium quantity.