Demand:
Tax as a Rise in Supply Cost Quantity Price ($) $1.03 $1.00 $0.93 Q0 Q1 D S0 S1 E0 E1 Consumer +$0.03 Producer −$0.07 $0.10 tax Tax $0.10 Tax as a Reduction of Demand Quantity $1.03 $1.00 $0.93 Q0 Q1 D0 S0 D1 E0 E1 Consumer +$0.03 Producer −$0.07 $0.10 tax Tax $0.10
Tax $0.10 · buyers pay $1.03 · sellers keep $0.93 · quantity 7.0→6.2
Buyers bear 3¢, sellers 7¢ — identical whether you tax the seller (left) or the buyer (right).