為提高健保保費負擔公平性，擴大計費基礎，2011年健保法修正案新增保險對象補充保險費，於2013年開始實施。保險對象之高頒獎金、兼職所得、執行業務收入、股利所得、利息所得及租金收入等所得項目，採就源扣繳方式課徵2%補充保險費。本文先就學理上討論補充保險費課徵方式是否符合健保財源籌措基本原則，從公平性、中立性、充足性、穩定性、節約性等五個面向分析，並由行政執行面列出未來補充保險費課徵時難以執行之處。本文希冀透過不同角度剖析課徵補充保險費可能問題，並提出相關建議，供主管機關未來擬定政策之參考。

In 2011, an Amendment to the "National Health Insurance Act" added a new supplementary premium by expanding the calculation base for employees. This is to be implemented on January 1, 2013. This approach will also reinforce the ability-to-pay principle and enlarge the premium base. An insured person will have to pay 2 percent of extra income, including that from interest, professional practice income, rent, stock dividends and bonuses exceeding the equivalent of four months' wages, as their supplementary premium for NHI. This study investigated the problems associated with this supplementary premium based on considerations of equity, neutrality, adequacy, stability, compliance and the administrative aspects, and provides suggestions for improvement.