不確定市場下以地價稅調節土地利用之研究

USING TAXATION TO ADJUSTING LAND DEVELOPMENT IN THE SITUATION OF UNCERTAINTY MARKET

地價稅的課徵，於古典學派的租稅觀點中，一般皆認為具中立性，不致影響土地資源的利用。然於土地利用之觀點，將土地稅與土地使用規劃視為解決市場失靈的兩大方法，透過Pigou稅之課徵以調節土地利用，即基於課稅不中立之觀點；故於近代經濟分析中，中立性問題引起廣泛的討論。相關研究主要採取土地現值模型，在土地所有權人追求土地折現值極大的假設下，探討課稅的效果，多數認為對土地課徵收益稅性質地價稅具中立性。然而，傳統以淨現值為基礎的投資決策模型，並未考慮投資不可逆轉（irreversibility）及可延遲性（deferability）的選擇權價值（option value）。是以，本文將選擇權價值納入模型，針對收益稅性質地價稅，探討不確定市場下之課稅效果。依分析結果，由於收益之不確定性，將延緩土地開發時機，且不確定性愈高，延緩效果越高。另就課稅效果而言，在不確定市場中對土地課徵收益稅性質地價稅，於開發前、後課徵相同稅率時，課稅仍具中立性；但開發前、後稅率不同時，其不具中立性效果將因市場不確定性而擴大。

From the viewpoint of classical economics, it is assumed that taxation on land value is neutral toward resource allocation. However, this argument has been criticized by the modern economics, which maintains that neutrality discourse is a controversial issue. Several papers have indicated that it has lacked of its consideration on the issue of irreversible and deferrable investment decisions. This paper is based upon this criticism, and it not only focuses on the land present value model but also applies real option theory to extend an optimal model under uncertainty market. The result demonstrates that development is postponed when the market is in the condition of uncertainty. Under uncertainty market, taxation on land value before and after development does show neutral effect if it contains uniform tax rates. However, the result shows that differences of the pre- and post-development tax rates do have non-neutral consequences. It is also important to note that the larger of the uncertainty of the market the greater effects on the fluctuating characteristic of neutrality.