Cette thèse est une collection de trois articles en macroéconomie et finances publiques. Elle développe des modèles d'Equilibre Général Dynamique et Stochastique pour analyser les implications macroéconomiques des politiques d'imposition des entreprises en présence de marchés financiers imparfaits. Le premier chapitre analyse les mécanismes de transmission à l'économie, des effets d'un ré-échelonnement de l'impôt sur le profit des entreprises. Dans une économie constituée d'un gouvernement, d'une firme représentative et d'un ménage représentatif, j'élabore un théorème de l'équivalence ricardienne avec l'impôt sur le profit des entreprises. Plus particulièrement, j'établis que si les marchés financiers sont parfaits, un ré-échelonnement de l'impôt sur le profit des entreprises qui ne change pas la valeur présente de l'impôt total auquel l'entreprise est assujettie sur toute sa durée de vie n'a aucun effet réel sur l'économie si l'état utilise un impôt forfaitaire. Ensuite, en présence de marchés financiers imparfaits, je montre qu'une une baisse temporaire de l'impôt forfaitaire sur le profit des entreprises stimule l'investissement parce qu'il réduit temporairement le coût marginal de l'investissement. Enfin, mes résultats indiquent que si l'impôt est proportionnel au profit des entreprises, l'anticipation de taxes élevées dans le futur réduit le rendement espéré de l'investissement et atténue la stimulation de l'investissement engendrée par la réduction d'impôt. Le deuxième chapitre est écrit en collaboration avec Rui Castro. Dans cet article, nous avons quantifié les effets sur les décisions individuelles d'investis-sement et de production des entreprises ainsi que sur les agrégats macroéconomiques, d'une baisse temporaire de l'impôt sur le profit des entreprises en présence de marchés financiers imparfaits. Dans un modèle où les entreprises sont sujettes à des chocs de productivité idiosyncratiques, nous avons d'abord établi que le rationnement de crédit affecte plus les petites (jeunes) entreprises que les grandes entreprises. Pour des entreprises de même taille, les entreprises les plus productives sont celles qui souffrent le plus du manque de liquidité résultant des imperfections du marché financier. Ensuite, nous montré que pour une baisse de 1 dollar du revenu de l'impôt, l'investissement et la production augmentent respectivement de 26 et 3,5 centimes. L'effet cumulatif indique une augmentation de l'investissement et de la production agrégés respectivement de 4,6 et 7,2 centimes. Au niveau individuel, nos résultats indiquent que la politique stimule l'investissement des petites entreprises, initialement en manque de liquidité, alors qu'elle réduit l'investissement des grandes entreprises, initialement non contraintes. Le troisième chapitre est consacré à l'analyse des effets de la réforme de l'imposition des revenus d'entreprise proposée par le Trésor américain en 1992. La proposition de réforme recommande l'élimination des impôts sur les dividendes et les gains en capital et l'imposition d'une seule taxe sur le revenu des entreprises. Pour ce faire, j'ai eu recours à un modèle dynamique stochastique d'équilibre général avec marchés financiers imparfaits dans lequel les entreprises sont sujettes à des chocs idiosyncratiques de productivité. Les résultats indiquent que l'abolition des impôts sur les dividendes et les gains en capital réduisent les distorsions dans les choix d'investissement des entreprises, stimule l'investissement et entraîne une meilleure allocation du capital. Mais pour être financièrement soutenable, la réforme nécessite un relèvement du taux de l'impôt sur le profit des entreprises de 34\% à 42\%. Cette hausse du taux d'imposition décourage l'accumulation du capital. En somme, la réforme engendre une baisse de l'accumulation du capital et de la production respectivement de 8\% et 1\%. Néanmoins, elle améliore l'allocation du capital de 20\%, engendrant des gains de productivité de 1.41\% et une modeste augmentation du bien être des consommateurs. / This thesis is a collection of three papers in macroeconomics and public finance. It develops Dynamic Stochastic General Equilibrium Models with a special focus on financial frictions to analyze the effects of changes in corporate tax policy on firm level and macroeconomic aggregates. Chapter 1 develops a dynamic general equilibrium model with a representative firm to assess the short-run effects of changes in the timing of corporate profit taxes. First, it extends the Ricardian equivalence result to an environment with production and establishes that a temporary corporate profit tax cut financed by future tax-increase has no real effect when the tax is lump sum and capital markets are perfect. Second, I assess how strong the ricardian forces are in the presence of financing frictions. I find that when equity issuance is costly, and when the firm faces a lower bound on dividend payments, a temporary tax cut reduces temporary the marginal cost of investment and implies positive marginal propensity of investment. Third, I analyze how do the intertemporal substitution effects of tax cuts interact with the stimulative effects when tax is not lump-sum. The results show that when tax is proportional to corporate profit, the expectations of high future tax rates reduce the expected marginal return on investment and mitigate the stimulative effects of tax cuts. The net investment response depends on the relative strength of each effect. Chapter 2 is co-authored with Rui Castro. In this paper, we quantify how effective temporary corporate tax cuts are in stimulating investment and output via relaxation of financing frictions. In fact, policymakers often rely on temporary corporate tax cuts in order to provide incentives for business investment in recession times. A common motivation is that such policies help relax financing frictions, which might bind more during recessions. We assess whether this mechanism is effective. In an industry equilibrium model where some firms are financially constrained, marginal propensities to invest are high. We consider a transitory corporate tax cut, funded by public debt. By increasing current cash flows, corporate tax cuts are effective at stimulating current investment. On impact, aggregate investment increases by 26 cents per dollar of tax stimulus, and aggregate output by 3.5 cents. The stimulative output effects are long-lived, extending past the period the policy is reversed, leading to a cumulative effect multiplier on output of 7.2 cents. A major factor preventing larger effects is that this policy tends to significantly crowd out investment among the larger, unconstrained firms. Chapter 3 studies the effects of the 1992's U.S. Treasury Department proposal of a Comprehensive Business Income Tax (CBIT) reform. According to the U.S. tax code, dividend and capital gain are taxed at the firm level and further taxed when distributed to shareholders. This double taxation may reduce the overall return on investment and induce inefficient capital allocation. Therefore, tax reforms have been at the center of numerous debates among economists and policymakers. As part of this debate, the U.S. Department of Treasury proposed in 1992 to abolish dividend and capital gain taxes, and to use a Comprehensive Business Income Tax (CBIT) to levy tax on corporate income. In this paper, I use an industry equilibrium model where firms are subject to financing frictions, and idiosyncratic productivity and entry/exit shocks to assess the long run effects of the CBIT. I find that the elimination of the capital gain and dividend taxes is not self financing. More precisely, the corporate profit tax rate should be increased from 34\% to 42\% to keep the reform revenue-neutral. Overall, the results show that the CBIT reform reduces capital accumulation and output by 8\% and 1\%, respectively. However, it improves capital allocation by 20\%, resulting in an increase in aggregate productivity by 1.41\% and in a modest welfare gain.

Satire and counsel recur together in the secular literature of the High and Late Middle Ages. I analyze their collocation in Latin, Old Occitan, and Middle English texts from the twelfth to the fifteenth century in works by Walter Map, Alan of Lille, John of Salisbury, Daniel of Beccles, John Gower, William of Poitiers, Thomas Hoccleve, and John Skelton. As types of discourse, satire and counsel resemble each other in the way they reproduce scenarios of social interaction. Authors combine satire and counsel to reproduce these scenarios according to the protocols of real-life social interaction. Informed by linguistic pragmatics, discourse analysis, sociolinguistics and cultural anthropology, I examine the relational rhetoric of these texts to uncover a sometimes complex and reflective ethical discourse on power which sometimes implicates itself in the practices it condemns. The dissertation draws throughout on sociolinguistic methods for examining verbal interaction between unequals, and assesses what this focus can contribute to recent scholarly debates on the interrelation of social and literary practices in the later Middle Ages. In the first chapter I introduce the concepts and methodologies that inform this dissertation through a detailed consideration of Distinction One of Walter Map’s De nugis curialium . While looking at how Walter Map combines discourses of satire and counsel to negotiate a new social role for the learned cleric at court, I advocate treating satire as a mode of expression more general than ‘literary’ genre and introduce the iii theories and methods that inform my treatment of literary texts as social interaction, considering also how these approaches can complement new historicist interpretation. Chapter two looks at how twelfth-century authors of didactic poetry appropriate relational discourses from school and household to claim the authoritative roles of teacher and father. In the third chapter, I focus on texts that depict relations between princes and courtiers, especially the Prologue of the Confessio Amantis which idealizes its author John Gower as an honest counselor and depicts King Richard II (in its first recension) as receptive to honest counsel. The fourth chapter turns to poets with the uncertain social identities of literate functionaries at court. Articulating their alienation and satirizing the ploys of courtiers—including even satire itself—Thomas Hoccleve in the Regement of Princes and John Skelton in The Bowge of Court undermine the satirist-counselor’s claim to authenticity. In concluding, I consider how this study revises understanding of the genre of satire in the Middle Ages and what such an approach might contribute to the study of Jean de Meun and Geoffrey Chaucer.

Satire and counsel recur together in the secular literature of the High and Late Middle Ages. I analyze their collocation in Latin, Old Occitan, and Middle English texts from the twelfth to the fifteenth century in works by Walter Map, Alan of Lille, John of Salisbury, Daniel of Beccles, John Gower, William of Poitiers, Thomas Hoccleve, and John Skelton. As types of discourse, satire and counsel resemble each other in the way they reproduce scenarios of social interaction. Authors combine satire and counsel to reproduce these scenarios according to the protocols of real-life social interaction. Informed by linguistic pragmatics, discourse analysis, sociolinguistics and cultural anthropology, I examine the relational rhetoric of these texts to uncover a sometimes complex and reflective ethical discourse on power which sometimes implicates itself in the practices it condemns. The dissertation draws throughout on sociolinguistic methods for examining verbal interaction between unequals, and assesses what this focus can contribute to recent scholarly debates on the interrelation of social and literary practices in the later Middle Ages. In the first chapter I introduce the concepts and methodologies that inform this dissertation through a detailed consideration of Distinction One of Walter Map’s De nugis curialium . While looking at how Walter Map combines discourses of satire and counsel to negotiate a new social role for the learned cleric at court, I advocate treating satire as a mode of expression more general than ‘literary’ genre and introduce the iii theories and methods that inform my treatment of literary texts as social interaction, considering also how these approaches can complement new historicist interpretation. Chapter two looks at how twelfth-century authors of didactic poetry appropriate relational discourses from school and household to claim the authoritative roles of teacher and father. In the third chapter, I focus on texts that depict relations between princes and courtiers, especially the Prologue of the Confessio Amantis which idealizes its author John Gower as an honest counselor and depicts King Richard II (in its first recension) as receptive to honest counsel. The fourth chapter turns to poets with the uncertain social identities of literate functionaries at court. Articulating their alienation and satirizing the ploys of courtiers—including even satire itself—Thomas Hoccleve in the Regement of Princes and John Skelton in The Bowge of Court undermine the satirist-counselor’s claim to authenticity. In concluding, I consider how this study revises understanding of the genre of satire in the Middle Ages and what such an approach might contribute to the study of Jean de Meun and Geoffrey Chaucer.

思及當前捉襟見肘的財政窘境，無可避免地，債台高築的臺灣實陷入飲鴆止渴般以債養債之無限迴圈中，導致政府政策效能不彰、社會福利運作生弊亦無可厚非；於『公共債務法』之財政規範下，臺灣業已瀕臨法定舉債門檻，故不論是對短期政府支出之排擠、扭曲性稅率之稽徵抑或對長期經濟成長的斲傷，皆是身為中華民國國民真正惶悚不安之所在。 職是之故，本研究係採用一納入政府財政部門及貨幣當局之擴充『實質景氣循環模型』，藉以Sidrauski（1967）所提出的貨幣效用函數為出發點，將實質餘額引進理論模型，並透過計量操作捕捉實證期間起於西元1971年第一季迄至2007年第四季之政府政策函數，過程中，我們不難發現政府購買性支出及稅率皆存在相當的持續性，且對政府未償公債餘額之高低作出某種程度的反應。亦即，若政府實施公債融通政策，俾使期初公債餘額較高之際，則本期甚或往後各期的政府支出將遭受抑制和排擠，尤有甚者，政府勢必擬以提高未來稅率以茲挹注該債務之還本付息所造成的財政缺口；是以，本研究著眼於引進公債餘額對政府支出及稅率存在反饋作用下，財政政策與貨幣政策之總體效果及各總體變數之動態調整過程的風貌。即便公債發行或賒借為政府提供一財務週轉工具以裨益財政政策保有更靈活之彈性，然據模型所產生的結果顯示，就長期而論，政府必須維持一穩定之未償公債餘額，即公債水準具備『均數復歸』性質，而該財政目標係透過削減未來政府支出、調整扭曲性稅率及鑄幣稅融通政策方得以達成預算平衡，準此，該設定將造成公債融通之減稅政策對經濟體系具有實質效果，『公債融通』管道亦『非中立性政策』，從而傳統『李嘉圖等值定理』於本模型中無法成立。 就政策面層次而言，本研究試圖放寬『反饋法則』與政策係數之設定，以檢視透過不同程度之政府支出、稅率甚至貨幣供給途徑的改變來平衡因增加公債發行所造成的財政赤字，對經濟體系之長短期效果有何迥異處；是文亦藉由衝擊反應函數分別探討於政府支出增加、減稅措施及貨幣擴張之下，政策的傳遞機制與各總體變數之動態性質，顯然地，就高債務比率前提下，當政府戮力於刺激景氣而欲積極實施立竿見影的總體經濟政策之際，卻常因狃於急效而欲速不達，非但政策效果有限，亦可能使體系落入更為不景氣的田地，從而，財政惡化不啻為經濟危機的導火線也就不言而喻。再者，貨幣政策對體系之實質變數具有一定程度的作用，是故，本模型於短期內無法一窺『貨幣中立性』之堂奧，唯長期始得以復見。總括言之，政府亟須奉『健全財政』為圭臬，擬定政策時更得戒慎恐懼，並適切權衡利弊得失，以茲裨益有更具信心的經濟表現。 此外，本研究亦透過『效準』實驗以評估模型『配適度』之良窳，即便於反覆疊代法下，該模擬表現係瑕瑜互見而不盡完美，卻也大抵符合景氣循環之『典型化特徵』；然就實質景氣循環模型所為人詬病之勞動市場一隅而論，引進公債之反饋法則下的財政政策操作，無疑地改善了傳統工時與工資率動輒高度正相關之本質，從而獲致相對較低之理論相關係數，亦朝實證資料所呈現工時與工資率存在幾近零相關甚或低度負相關之表徵更邁進一大步。 / With current financial difficulties beyond government capability, it is inevitable that the already deep-in-debt Taiwan opted for momentary relief by paying debt through debt financing and ended up in an infinite loop, causing spiral-down performances in government policies and faulty operations of social welfare instruments. Taiwan has been on the verge of reaching the statutory upper limit of debt financing according to “The Public Debt Act” regulations and all nationals are becoming anxious about such impacts as crowding out of short-run government spending, levying of distorting taxes, and damages on long-run economic growth. To better understand the debt’s impacts, this research uses the “Real Business Cycle Model” extended by taking government treasury agency and monetary institution into account. Starting with Money In Utility Function (MIUF) as proposed by Sidrauski (1967) to introduce real money balance into the theoretical model and, in the process of econometric manipulation, to detect empirical governmental policy functions in the period between the first quarter, 1971 and the fourth quarter, 2007, it is not hard to discover that there are considerable persistence in both government purchases and tax rates, with manifestation of certain degree of responses to the total amount of outstanding bonds the government has yet to pay. In other words, a governmental bond financing policy designed to render high initial bonds outstanding tends to cause suppression and crowding out of government spending in current and even later periods. Furthermore, the government is bound to plan on raising taxes in the future in order to cut financial deficit gap caused by paying back the principles and interests of the debt. Therefore, this study focuses on presenting the macroeconomic effects of fiscal policies and monetary policies, as well as the dynamic adjustment processes of macroeconomic variables based on the impact of feedback effect of bonds outstanding on government spending and tax rates. Even thought public bonds issuance or debt financing serves as a governmental fiscal instrument for financial turnover to ensure flexibility of fiscal policies, our model shows that the government should, from a long-run perspective, maintain a stable amount of bonds outstanding. Put in a different way, the level of bonds outstanding shows “mean-reverting” characteristics which rely on future government spending cut, distorting tax adjustment and seigniorage financing policy to achieve balance of budget. As a result, such setup would cause the bond-financing backed tax deduction policies to create practical effects on economies and, as the bond financing instruments are “Non-Neutrality” policies, would render the “Ricardian Equivalence Theorem” invalid in our model. In the policy aspect, this study tries to relax both “feedback rules” and setup of policy parameters for investigating the differences between long-run and short-run effects on the economy by different degrees of changes in government spending, tax rates and even money supply channels which are used to balance the fiscal deficit caused by increased bond issuance. This article also studies, through the impulse response function, the policy propagation mechanism and the dynamics of key macroeconomic variables under the situation of government spending increase, tax deduction and monetary expansion. It is obvious that the government, in the case of high debt ratios and when making all endeavors to spur economy by implementing macroeconomic policies aimed for instant results, is accustomed to seeking quick fixes only to achieve very limited effects, sometimes even to drive the economy into further recession. It is therefore evident that fiscal degradation could lead to economic disaster. Moreover, as the monetary policies have certain degrees of influence on real variables of the economy, this model will not be able to clearly analyze the “neutrality of money” in such a short period of time. The effect will only reveal in the long run. In summary, the government should keep “sound finance” as the highest guiding principle and be extremely cautious in formulating policies in order to weigh all pros and cons discreetly, thus help to achieve a benefiting economic performance that generates more confidence. Furthermore, this study assesses “goodness of fit” of the model through a “calibration” experiment. Although the simulation results show, under recursive method, intermingled good and poor occasions that are beyond satisfaction, they generally agree with the “typical characteristics” of business cycles. However, in the aspect of long-criticized labor market of the real business cycle model, the fiscal policy operation under feedback rules with introduction of public debts for sure has greatly improved on the conventional intrinsic property of high correlation between labor hours and real wage rates, by delivering a relatively low theoretical correlation coefficient, which is a big step towards the empirical results of almost zero or even weakly negative correlation between labor hours and real wage rates.