Published papers

  This paper implements a microsimulation analysis based on individual data from the Japan Household Panel Survey (JHPS/KHPS) to investigate on income redistribution effects of the Japanese personal income tax reforms in the 2010s. The analyses of this paper cover reforms of various income deductions, and the increases in rates for dividend and capital gain taxation and the maximum income tax rate.  We find that a series of personal income tax reforms in the 2010s has been estimated to be reduced the Gini coefficient of equivalent household disposable income from 0.3278 to 0.3253, and income inequality has narrowed. Also, the tax reforms for income in 2020 and its related reforms of the social security system have had the largest effect on reducing income inequality among each reform. We obtain the results that the tax base effect is evaluated to be larger than the tax rate effect as a factor in the income redistribution effect through personal income tax reforms. However, the decline in the Gini coefficient is estimated to be limited, probably because the reforms did not expand tax credits but only reduced income deductions.

Economic indicators are essential for policymaking and strategic decisions in both the public and private sectors. However, due to delays in the release of government indicators based on macroeconomic factors, there is a high demand for timely estimates or “nowcasting”. Many attempts have been made to overcome this challenge using macro indicators and key variables such as keywords from social networks and search queries, but with a reliance on human selection. We present a fully data-driven methodology using non-prescribed search engine query data (Search Big Data) to approximate economic variables in real time. We evaluate this model by estimating representative Japanese economic indicators and confirm its success in nowcasting prior to official announcements, even during the COVID-19 pandemic, unlike human-selected variable models that struggled. Our model shows consistent performance in nowcasting indices both before and under the pandemic before government announcements, adapting to unexpected circumstances and rapid economic fluctuations. An exhaustive analysis of key queries reveals the pivotal role of libidinal drives and the pursuit of entertainment in influencing economic indicators within the temporal and geographic context examined. This research exemplifies a novel approach to economic forecasting that utilizes contemporary data sources and transcends the limitations of existing methodologies.

本稿では，炭素税に仕入税額控除と輸出免税と輸入時課税を組み込んだ，仕向地主義炭素税の概念を説明するとともに，経済理論モデルによって，従来の仕入税額控除と輸出免税と輸入時課税がない炭素税よりも，仕向地主義炭素税の方が，経済厚生の面でも望ましいことを裏付ける分析結果を示した。特に，仕入税額控除と輸出免税と輸入時課税がない炭素税では，付加価値税との間で課税の累積を引き起こしたり，他国に輸出する際に国際競争上不利になったりする現象が生じる。本稿では，その論理を記述的に説明するだけではなく，経済理論モデルを基にしても確認した。　本稿で分析した開放経済における複占企業モデルでは，複占企業間の戦略的行動によって各国の税率に反応して財の需給や価格が変化しうるため，仕向地主義炭素税が経済厚生の面で常に望ましいというわけではない。本稿で確認したところ，経済厚生の面で仕向地主義炭素税の有利性が低減するのは，各国の経済構造がかなり異なり，炭素税を課していない国の経済規模が顕著に小さい場合である。むしろ，今後の日米欧や経済規模の大きい新興国の間で，炭素税（をはじめとするカーボンプライシング）や炭素国境調整措置のあり方を検討することを踏まえれば，経済規模の大きさが比較的近い国同士の間では，仕向地主義炭素税の方が望ましいという本稿の結論が，重要な意味を持つ。

本稿は，法人税申告書の個票データを用い，所得金額または欠損金額，法人税額の分布を資本金額や業種や同非区分（非同族会社，特定同族会社，同族会社等）などの属性ごとに集計・頻度表等を作成し，さらに欠損金の繰越控除や法人税額等について実態を分析することを目的とする。まず，利用可能な2014～2020年度の法人税申告書のデータから，合併，年度内複数回申告，欠測等を補正してパネルデータを構築した。　次に，この全数調査から全法人（連結法人と外国法人と休業・清算中の法人を除く）について分析したところ，以下の結果を得た。会社標本調査等では公表されていない欠損金額の法人数の分布を示し，欠損金額（所得金額）が0円となる法人に集群（bunching） しているように見受けられた。ただ，欠損金額が0円となる欠損法人は，資本金1億円以下の法人で多く，資本金1億円超の法人で少なくなっていた。7年連続で欠損法人となった法人は，全法人の36.5％を占め，資本金規模が小さいほどその比率が高かった。7年連続して欠損控除を適用した法人は，全法人の1.1％にすぎず，7年間1度も欠損控除を適用しなかった法人は，全法人の21.2％であった。資本金1億円超と1億円以下の法人が，年度間でどう遷移したかを分析したところ，資本金1億円超の法人が減資して翌年度に資本金1億円以下となる遷移確率は，各年度で4%弱から5%強となっている一方で，資本金1億円以下の法人が増資して翌年度に資本金1億円超となる遷移確率は極めて小さかった。また，利益計上法人よりも欠損法人の方が，資本金1億円超の法人が減資して翌年度に資本金1億円以下となる遷移確率が高かった。さらに，法人税額階級別の法人数や法人税額の分布を示し，法人税を500万円超払う法人が，全法人の5％程度を占め，全法人の法人税の約95％を納めていた。加えて，資本金規模が大きいほど500万円超払う法人の構成比が高かったことも明らかにした。

日本の中央政府から地方政府への国庫支出金分配と選挙結果のフィードバック関係について、諸仮説を計量的な手法により客観的に検証した。1956年度から1993年度のデータを基に回帰分析を行った結果、全期間を通じて「（議員定数と無関係に）与党議員の数が多い県ほど補助金が多く分配されていた」、保革伯仲期には「野党との競争が激しい県ほど補助金が多く分配されていた」という仮説が支持された。「補助金の増加が与党議員の得票率に影響を与えた」、「投票者は補助金政策に基づいて投票した」という仮説を支持する証拠は得られなかった。

This paper investigates the effects of corporate tax reform in Japan, wherein the (effective) corporate income tax rate decreases from 34.62% to 29.74% and the rates of size-based business taxation (levy on the sum of labor cost and other factor payment) rise at 2.5 times. We implement a simulation based on a dynamic macroeconomic model including capital structure (i.e., choices of equity, debt, and retained earnings) in the proposed model in order to implement investment, and measure the incidence of corporate income tax on labor income. This tax reform implies that the tax base is shifted from corporate income to labor cost, because it accounts for the majority of factor payments for most firms on which the size-based business taxation or “pro-forma” taxation is imposed. We find that the benefit on labor income from reduction of corporate income taxation is decreased by about 30% by expansion of the size-based business taxation from a simulation result. A reason behind the phenomena is distortion stemming from the size-based business taxation. Labor income increases due to lowering (effective) corporate income tax rate, nevertheless it loses due to rising rates of size-based business taxation.

The second arrow of Abenomics is flexible fiscal policy. However, it does not mean just fiscal stimulus as the Abe administration decided on the fiscal consolidation target of achieving a primary surplus by fiscal year 2020. Improving the primary balance implies making government debt more sustainable. Although the consumption tax rate was raised from 5% to 8% in April 2014, the Abe administration has decided twice to postpone increasing the consumption tax from 8% to 10%. In addition, a fiscal stimulus package was implemented. We use a Fiscal Stance Index to examine fiscal policy from the viewpoint of fiscal sustainability and a Markov switching model to examine fiscal policy from the viewpoint of the fiscal theory of the price level, and find that the Abe's fiscal stance is not Ricardian.

We investigate effects of reform of spousal tax deductions, which were listed in the 2017 tax reform outline, and deductions for persons on income inequality in Japan by using a microsimulation. The Japan Household Panel Survey (JHPS) in 2014 is used in the analyses. We find that the reform of exemptions for spouses does not substantially correct income disparity. It implies that the spousal tax deductions after the reform still remain as deductions from income (tax allowances), which have weaker effects in correcting income disparity relative to deductions from tax. In addition, we analyze a microsimulation which changes deductions from income to tax credits. That is, the reform in which deductions from income are abolished and tax credits based on household composition are newly established on only deductions for persons. We obtain the result that the Gini coefficient of the equivalent household disposable income slightly decreases. In order to decrease the Gini coefficient more, even deductions from earnings (deduction for employment income and deduction for public pensions) need to be abolished and tax credits need to be newly established. Moreover, according to a microsimulation, a "discount on social insurance premiums (tentative name)," which provide for partial compensation of premiums by using revenue from the personal income tax, acts to correct income inequality.