配對交易策略為一被廣為使用的交易策略，其特性為使用數個關聯性高的資產同時建立多空部位，藉此消除大部分的市場風險，賺取與市場趨勢無關聯性的報酬；本研究欲探討共整合法配對交易策略應用於兩類標的資產上之可行性及其功效:台灣證券交易所掛牌的6檔陸股ETF、以及COMEX黃金期貨與CME日幣期貨之組合。本研究使用之配對交易策略應用於6檔陸股ETF大部分參數設定下可獲得正報酬，獲利性卻不如預期，且共整合性質較佳之配對無法保證其交易績效亦較佳；COMEX黃金期貨及CME日幣期貨雖相對共整合性質不佳，仍以原策略測試可獲得較優秀的績效，此結果顯示共整合法配對交易策略於兩類資產上可行性皆不高，而配對交易策略於黃金、日幣組合上可能仍有其功效，尚須以不同方法進行驗證。 / Pairs trading strategy is one kind of market neutral strategy which take both long and short positions in two or more highly correlated assets. By doing this pairs trading strategy can eliminate market risk and make profits which are not correlated with market trends. This paper aims to figure out if pairs trading strategy work well on China ETFs listed in TWSE and the COMEX gold-CME yen future pair. We use the cointegration approach to test and simulate trading performance on the securities mentioned. The result shows that pairs trading strategy profit on China ETFs under most of the parameters, but the returns are insufficient. Furthermore, good cointegration property in the input periods can’t guarantee better performances in the outputs periods. For COMEX gold future and CME yen future, cointegration property in the input periods are worse than China ETFs, but using the same strategy we find a more profitable outcome. The empirical result indicate that pairs trading strategy might still work on gold and yen, but the cointegration approach is not suitable for these two groups of assets.

Les pays africains de la zone CFA ont connu ces dernières années de multiples transformations économiques d'une part à travers les mesures initiées par les bailleurs de fonds bilatéraux et multilatéraux et d'autre part à travers les politiques d'intégration économique et monétaire. Ainsi, en partant de l'hypothèse selon laquelle du fait de ces nombreuses interventions, ces systèmes économiques incorporent divers phénomènes tels que les changements structurels et les dépendances inter-économies, nous avons étudié leurs principales implications sur la croissance, la convergence et la prévisibilité du taux de croissance. L'accent est d'abord mis sur les traits majeurs des politiques d'intégration dans le cadre d'une union monétaire tout en soulignant les éventuelles incidences de telles politiques sur la dynamique économique des pays membres principalement en termes de modélisation économétrique de la croissance et de la convergence. Les différentes études réalisées sur la base d'outils économétriques adaptés ont permis d'aboutir à des résultats nouveaux relatifs au processus de croissance et de convergence de ces économies comparativement à ceux basés sur les outils classiques de modélisation économétrique. Il ressort également de cette étude que la présence de facteurs communs et de ruptures structurelles est fortement liée aux politiques d'intégration mises en oeuvre au sein de la zone CFA. Ces résultats révèlent aussi que les chocs produisent des effets hétérogènes et ont généralement des dates d'occurrence différentes selon les pays et qu'il est nécessaire de faire varier les réponses de politique économique d'un pays à l'autre pour une croissance durable et mieux partagée. / During the recent years, african countries in the CFA zone have experienced many economic changes on the one hand through the measures initiated by bilateral and multilateral donors and on the other hand through the economic and monetary integration policies. Thus, relying on the assumption that because of these interventions, the economic systems incorporate various phenomena such as structural change and economic interdependencies, we studied their major implications on growth, convergence and growth predictability. Emphasis is first placed on the major features of integration policies in a monetary union, while stressing the possible implications of such policies on the economic dynamics of member countries mainly in terms of econometric modelling of growth and convergence. The different studies conducted on the basis of appropriate econometric tools led to new results concerning the process of growth and convergence of these economies compared to those based on standard tools of econometric modelling. It is also clear from this study that the presence of common factors and structural breaks is strongly linked to integration policies implemented in the CFA zone. These results also indicate that shocks produce heterogeneous effects on economies with various dates of occurrence and that it is necessary to vary the policy responses from one country to another for sustainable and shared growth.

在全球化趨勢下，地方競爭將取代國家的競爭，地方是國家能否與全球競爭之關鍵，提高地方的競爭優勢與發展地方經濟是各國政府努力的目標。財政制度對長期地方發展扮演重要角色。透過政府間的權限與財源之劃分，一方面可使政府所提供之財貨和勞務適應不同地方人民偏好之制度效率目標，進而使所得成長；另方面可維持全國一致性和地方間的發展平衡，避免各地方所得分配過度懸殊的公平目標。良好的財政制度必須能提升各政府部門自我負責性及經濟效率，促進地方所得成長卻不會傷害地方間均衡發展之公平目標。本文以單根檢定法分析發現民國72年至93年間我國政府部門財政制度變遷，以及民國88年以後財政收支劃分法修正後財政制度調整，的確使政府間財政資源分配更趨向公平，但多個地方政府間財政自主程度並未提升且差異大。又透過民國79年至93年23個直轄市與縣市地方政府長期追蹤資料，分析發現我國財政制度在地方發展上扮演非常重要角色。財政分權制度與地方政府財政收支制度的確對各地方所得成長率與地方所得分配有顯著影響效果。但地方政府財政收支制度無法發揮效率，對地方發展有不利影響。88年財政制度調整後地方財政制度對地方發展之不利影響並未有所改善。本文根據研究結果提出制度建議，以作為未來制定地方財政制度與地方發展政策之參考。 / Local governments faced severe fiscal imbalance problems for a long time, caused in part by long-term structural imbalances between their spending and revenue requirements. May be financial structural has positive consequences on local economic development. The article examines the relationship between the fiscal structure of local government and local economic development. Although most prior empirical studies present inconsistent findings about the effects of local taxing and spending policies, but more empirical works conclude that local income growth relates negatively to tax increases if the revenue finances income redistribution, but not if the revenue finances public services. The study examines these issues with more recent panel data of Taiwan and with more careful attention the effects of fiscal decentralization. We conclude that local economic development relates negatively to local tax increases if the revenue finances local public service . Local Financial structural and fiscal decentralization have negative consequences on local economic development.

本論文的研究主軸圍繞於自我迴歸模型的估計與推論上。文獻上自我迴歸模型的估計多直接採用最小平方法, 但此估計方式卻有兩個缺點:(一)當序列具單根時,最小平方估計式的漸近分配為非正規型態,因此檢定時需透過電腦模擬得到臨界值;(二)最小平方估計式雖具一致性,但卻有嚴重的有限樣本偏誤問題。有鑑於此,我們提出一種「二階差分轉換估計式」,並證明該估計式的偏誤遠低於前述最小平方估計式,且在序列為粧定與具單根的環境下具有相同的漸近常態分配。此外,二階差分轉換估計式相當適合應用於固定效果追蹤資料模型,而據以形成的追蹤資料單根檢定在序列較短的情況下仍有不錯的檢定力。 本論文共分四章,茲分別簡單說明如下: 第1章為緒論,回顧文獻上估計與推論自我回歸模型時的問題,並說明本論文的研究目標。估計自我迴歸模型的傳統方式是直接採取最小平方法,但在序列具單根的情況下由於訊息不隨時間消逝而快速累積,使估計式的收斂速度高於序列為恒定的情況。不過,這也導致最小平方估計式的漸近分配為非標準型態,並使得進行假設檢定前必須先透過電腦模擬來獲得臨界值。其次,最小平方估計式雖具一致性,但在有限樣本下卻是偏誤的。實證上, 樣本點不多是研究者時常面臨的窘境,並使得小樣本偏誤程度格外嚴重。本章中透過對前述問題形成因素的瞭解,說明解決與改善的方法,亦即我們提出的「二階差分轉換估計式」。 第2章主要目的在於推導二階差分轉換估計式之有限樣本偏誤。我們亦推導了多階差分自我迴歸模型下二階段最小平方估計式(two stage least squares, 2SLS)與 Phillips andHan (2008)採用的一階差分轉換估計式之偏誤,以同時進行比較。本章理論與模擬結果皆顯示,一階與二階差分轉換估許式與2SLS之 $T^{−1}$ 階偏誤程度皆低於以最小平方法估計原始準模型(level model)的偏誤,其中 T 為時間序列長度。另外,一階差分轉換估計式與二階差分轉換估計式在 $T^{−1}$ 階偏誤上,分別與一階和二階差分模型下2SLS相同,但兩估計式的相對偏誤程度則因自我相關係數的大小而互有優劣。同時,我們發現估計高於二階的差分模型對小樣本偏誤並無法有更進一步的改善。最後,即使在樣本點不多的情況下,本章所推導的偏誤理論對於實際偏誤仍有良好的近似能力。 第3章主要目的在於發展二階差分轉換估計式之漸近理論。與 Phillips and Han (2008) 採用之一階差分轉換估計式相似的是,該估計式在序列為恒定與具單根的情況下收斂速度相同,並有漸近常態分配的優點。值得注意的是, 二階差分轉換估計式的漸近分配為 N(0,2),不受任何未知參數的影響。另外,當序列呈現正自我相關時,二階差分轉換估計式相較於一階差分轉換估計式具有較小的漸近變異數,進而使得據以形成的檢定統計量有較佳的對立假設偵測能力。最後, 誠如 Phillips and Han (2008) 所述,由於差分過程消除了模型中的截距項,使得此類估計方法在固定效果的動態追蹤資料模型(dynamic panel data model with fixed effect) 具相當的發展與應用價值。 本論文第4 章進一步將二階差分轉換估計式推展至固定效果的動態追蹤資料模型。文獻上估計此種模型通常利用差分來消除固定效果後,再以一般動差法 (generalized method of moments, GMM) 進行估計。然而,這樣的估計方式在序列為近單根或具單根時卻面臨了弱工具變數(weak instrument)的問題,並導致嚴重的估計偏誤。相反的,差分轉換估計式所利用的動差條件在近單根與單根的情況下仍然穩固,因此在小樣本下的估計偏誤相當輕微(甚至無偏誤)。另外,我們證明了不論序列長度(T )或橫斷面規模(n)趨近無窮大,差分轉換估計式皆有漸近常態分配的性質。與單一序列時相同的是,我們提出的二階差分轉換估計式在序列具正自我相關性時的漸近變異數較一階差分轉換估計式小;受惠於此,利用二階差分轉換估計式所建構的檢定具有較佳的檢力。值得注意的是,由於二階差分轉換估計式在單根的情況下仍有漸近常態分配的性質,我們得以直接利用該漸近理論建構追蹤資料單根檢定。電腦模擬結果發現,在小 T 大 n 的情況下,其檢力優於文獻上常用的 IPS 檢定(Im et al., 1997, 2003)。 / This thesis deals with estimation and inference in autoregressive models. Conventionally, the autoregressive models estimated by the least squares (LS) procedure may be subject to two shortcomings. First, the asymptotic distribution of the LS estimates for autoregressive coefficient is discontinuous at unity. Test statistics based on the LS estimates thus follow nonstandard distributions, and the critical values obtained need to rely on Monte Carlo techniques. Secondly, as is well known, the LS estimates of autoregressive models are biased in finite samples. This bias could be substantial and leads to serious size distortion for the test statistics built on the estimates and forecast errors. In this thesis,we consider a simple newmethod ofmoments estimator, termed the “transformed second-difference” (hereafter TSD) estimator, that is without the aforementioned problems, and has many useful applications. Notably, when applied to dynamic panel models, the associated panel unit root tests shares a great power advantage over the existing ones, for the cases with very short time span. The thesis consists of 4 chapters, which are briefly described as follows. 1. Introduction: Overview and Purpose This chapter first reviews the literature and states the purpose of this dissertation. We discuss the sources of problems in estimating autoregressive models with the conventional method. The motivation to estimate the autoregressive series with multiple-difference models, instead of the conventional level model, is provided. We then propose a new estimator, the TSD estimator, which can avoid (fully or partly) the drawbacks of the LS method, and highlight its finite-sample and asymptotic properties. 2. The Bias of 2SLSs and transformed difference estimators in Multiple-Difference AR(1) Models In this chapter, we derive approximate bias for the TSD estimator. For comparisons, the corresponding bias of the two stage least squares estimators (2SLS) in multiple-difference AR(1) models and the transformed first-difference (TFD) estimator proposed by Chowdhurry (1987) are also given as by-products. We find that: (i) All the estimators considered are much less biased than the LS ones with the level regression; (ii)The difference method can be exploited to reduce the bias only up to the order of difference 2; and (iii) The bias of the TFD and TSD estimators share the same order at $O(T^{-1})$ as that of 2SLSs. However, to the extent of bias reductions, neither the 2 considered transformed difference estimators shows a uniform dominance over the entire parameter space. Our simulation evidence lends credible supports to our bias approximation theory. 3. Gaussian Inference in AR(1) Time Series with or without a Unit Root The goal of the chapter is to develop an asymptotic theory of the TSD estimator. Similar to that of the TFD estimator shown by Phillips and Han (2008), the TSDestimator is found to have Gaussian asymptotics for all values of ρ ∈ (−1, 1] with $\sqrt{T}$ rate of convergence, where ρ is the autoregressive coefficient of interest and T is the time span. Specifically, the limit distribution of the TSD estimator is N(0,2) for all possible values of ρ. In addition, the asymptotic variance of the TSD estimator is smaller than that of the TFD estimator for the cases with ρ > 0, and the corresponding t -test thus exhibits superior power to the TFD-based one. 4. Estimation and Inference with Moment Methods for Dynamic Panels with Fixed Effects This chapter demonstrates the usefulness of the TSD estimator when applying to to dynamic panel datamodels. We find again that the TSD estimator displays a standard Gaussian limit, with a convergence rate of $\sqrt{nT}$ for all values of ρ, including unity, irrespective of how n or T approaches infinity. Particularly, the TSD estimator makes use of moment conditions that are strong for all values of ρ, and therefore can completely avoid the weak instrument problem for ρ in the vicinity of unity, and has virtually no finite sample bias. As in the time series case, the asymptotic variance of the TSD estimator is smaller than that of the TFD estimator of Han and Phillips (2009) when ρ > 0 and T > 3, and the corresponding t -ratio test is thus more capable of unveiling the true data generating process. Furthermore, the asymptotic theory can be applied directly to panel unit root test. Our simulation results reveal that the TSD-based unit root test is more powerful than the widely used IPS test (Im et al, 1997, 2003) when n is large and T is small.

This study tests for the market efficiency of the Nairobi Securities Exchange (NSE) after the year 2000 to determine the effect of technological advancements on market efficiency. Data that is used is the NSE 20 share index over the period 2001 to 2015; and the NSE All Share Index (NSE ASI) from its initiation during 2008 to 2015. We cannot accept the Efficient Market Hypothesis (EMH) for the NSE using the serial correlation test, the unit root tests and the runs test. However, we can accept the EMH for the more robust variance ratio test. Overall, the results of the market efficiency are mixed. The most significant finding is that the efficiency of the NSE has increased since the year 2000 which suggests that advancements in technology have contributed to the increase in the market efficiency of the NSE. / Business Management / M. Com. (Business Management)