Although asymmetric information has been in discussion for a long time, comparison of its impacts on pricing and production between spot and forward sales has not been thoroughly investigated, especially in a transition economy like Vietnam where housing market has just shifted from state-controlled to market-oriented. The first objective of this study, therefore, is to model presale transaction in Vietnam in general and particularly in Hochiminh City (HCMC) to identify the most common presale risks, especially on asymmetric information. Second, it evaluates security of presale transaction from legal, organizational, and technical aspects. Finally, the research develops theoretical models to assess the impact of asymmetric information and risk diversification of the bank.

In this research, presale transaction procedure is modeled at three levels. This is done by breaking down the goal of the presale system, "to provide transactional security to parties involving in a presale transaction", into four functions that need to be fulfilled to achieve such goal. The four functions are juridical, fiscal, regulatory, and information management. Each function is further broken down into tasks that will have to be performed to fulfill each function. The tasks are either mandatory or, optional but necessary for the transaction. To obtain necessary data and information, three surveys were performed in April-May and November-December of 2011, and in April 2012. In total, 42 presale purchasers of 13 residential projects, six interviewees from two local developers, three respondents from two international real estate service firms in HCMC, five interviewees from three banks, one notary, one deputy of City Land Registry, and lastly one respondent from City Department of Construction (CDC), joined the surveys.

The forward transaction is evaluated at three aforementioned levels from legal, organizational, and technical aspects. Also, the research extends benchmark model presented by Chan, Fang, and Yang in 2008, to investigate the impacts of market demand uncertainty, capital appropriation, and developers' reputation. First, the model shows that the higher level of asymmetric information, the more expensive the property, the bigger project size regardless of selling methods, and the greater wealth transferred from purchasers to developer. The property market bubble in 2008 in HCMC proves such argument where many forward purchasers were paying high cost to hedge against price appreciation in future (due to their belief in shortage of future supply) despite the fact of oversupply. However, asymmetric information problem is not effectively eliminated due to lack of CDC's legal liability for sharing residential project information to purchasers and CDC's paper-based information system that make information less accessible.

Second, it is found that the higher downpayment the bigger difference in project size between two selling methods, the more advantageous the forward sale market than the spot sale, but the greater possibility of project abandonment. It is consistent with observation in HCMC where payment progress is often faster than construction progress but the advanced capital can be easily spent for inappropriate purposes. Also, thanks to this, many developers pursue projects that are beyond their financial capability. Consequently, rate of project completion in HCMC from 1996 to 2006 is less than 6%. However, appropriation of forward buyers' capital by developers is ineffectively prevented because project expenditure and revenues are not strictly controlled and supervised by forward purchasers nor authorized persons. This is because either fixed-payment scheme is acceptable without developers' additional liability or progress certificate is not a perquisite for payment. In addition, advanced payment is not required to be deposited into a single project account, and withdrawal of money from this account is not subject to supervision of buyers nor authorized persons (banks, real estate agent, or notaries). Moreover, information on project expenditure is surprisingly inaccessible to neither purchasers nor authorized person(s).

Regarding the effect of developer's reputation on borrowing interest rate, the higher the developer's reputation, the smaller the difference in project scale between forward sales and spot sales. This theoretical conclusion is supported by the fact that spot condominium market in HCMC is greatly concentrated by a small group of very reputable developers. On the other hand, in terms of reputation effect on buyers' willingness to pay, the model shows that the higher the developer's reputation the greater the difference in project scale and property price between two selling methods. It is because forward purchasers, but not spot buyers, are willing to pay higher for reputable developers. In addition, the higher reputation, the more advantageous the forward contract than the spot sales contract for both developers and purchasers. Unfortunately, under the existing system, developer's reputation is little recognized by laws (e.g. in project approval, and approval of building permit) and by relevant parties. Specifically, banks do not share information on financial performance of developers to purchasers; and CDC does not share information on past/current projects of developers to purchasers.

The study also develops a model to examine the risk diversification of banks while they finance both development and forward sales of projects. The model shows that the banks have incentive to collude with developers in appropriating buyers' capital in order to have a better risk balance. It is observed in HCMC that banks usually retain a portion of advance payment to reduce the developers' debt without consent from forward buyers. Unfortunately, the collusion is not easily eliminated because banks are not liable on behalf of purchasers for correctness of presale installments, supervision of project expenditure, nor completion of the project.

Based on both international (Hong Kong, United Kingdom, and Netherland) and domestic experiences, the research recommends the followings. First, project revenues and expenditures should be strictly managed by application of a single account for each project. All project-related payments must be deposited into this account. Withdrawal of money in this account is subject to supervision of buyers or authorized person(s) (for example a trusted bank in presale or management board in operation), and only for strictly defined purposes. In addition, progress certificate and/or occupancy permit must be a prerequisite for installments or the final payment, respectively. Information on revenues and expenditures of the project must be accessible to responsible authorities and the purchasers.

Second, there is surgical need for the reallocation of responsibility among involving parties. The highest legal responsibility for evaluating the financial viability of the project should be shifted from the CDC to banks. The best solution is to require developers to show bank guarantee for the completion of projects. This reallocation of responsibility is also good to prevent the aforementioned collusive behaviors by banks. In addition, it is preferred that presale contracts are certified by civil notaries, similar to the certification of sale contracts between individuals, rather than by CDC and transaction floors to guarantee the quality and impartiality of the certification, respectively.

Third, the reputation should be recognized or rewarded while government interventions to regulate property price should be limited or gradually reduced. This is because the market is able to capitalize reputation into price. In the long run, disreputable developers will be forced out of the market naturally. However, as the forward market is still in its infancy and developer's reputation is not easily recognized, softening the market entrance barrier for new developers should be carefully examined.

Fourth, indexing system for recording, storing and updating information related to project development should be redesigned to ensure consistency and uniformity across different authorities. This can be done by reduction of conflict in legal classification systems and/or by standardization (e.g. presale contract, progress certificate, and information disclosure). In addition, information infrastructure is better designed as centrally-oriented, interoperable and user-friendly systems, rather than a combination of discrete, non-shareable, unfriendly and distributed systems which are managed by many authorities at different levels of administration to promote smooth communication among relevant stakeholders. This system should be built and maintained in principle of cost recovery by providing information services to users with an appropriate fee.

For developers, it is better to price the property and to decide the scale of a project according to market uncertainty, downpayment rate, and their reputation. Also, investment in reputation must be based on selling methods since it is more profitable for presale market than for spot sale market.

For developers, it is better to price properties and to decide scale of projects according to market uncertainty, downpayment, and their reputation. Also, investment in reputation must be based on selling methods since the reputation investment is more profitable in presale market than in spot sale market. Finally, property developers, regardless of selling method, must invest more in reputation because reputational effect is currently weak in HCMC.

ベトナム国のように移行経済下にある市場においては、市場の取引手続きに関わる制度が未成熟であり、不動産取引市場においても、様々な問題が発生している。本研究は、ベトナム国ホーチミン市の不動産取引、特に前売り販売の手続き過程を対象に、そのプロセスにおけるリスクの実態を現地調査により明らかにし、不動産取引の手続き過程を法的、組織的、技術的さらに情報の非対称性に基づく経済学的モデルにより評価することを目的としている。

第1章は、序論であり、本研究の背景、目的と本研究で対象とする範囲、方法、構造を示している。

第2章では、不動産の前売り販売におけるリスクに関するこれまでの知見と研究を整理している。まず、不動産の前売り販売を行っている諸外国の制度を概観し、前売り販売システムにおける関係者である、開発業者、購入者、政府、金融機関が抱えるリスクを整理している。さらに、これらのリスクに対応する手法を諸外国の経験を文献調査により整理し、近年開発が盛んなベトナム国に対する示唆として取り纏めている。

第3章では、ベトナム国ホーチミン市における不動産の前売り販売手続き過程を3回の現地における実態調査により明らかにし、その詳細過程をリスクの観点から分析している。13の開発事業における42人の購入者、地元の開発事業者2社から6人、外資系不動産会社2社から3人、3つの金融機関から5人、市の土地登録課と建設課からそれぞれ1人のインタビュー対象者に対して、前売り販売取引の詳細な過程について調査を行っている。前売り販売手続きには、a)出資金契約、b)ローン無しの先払い契約、c)ローン付きの先払い契約の3つのタイプが存在し、それぞれの複雑なプロセスを明らかにするとともに、制度が抱える矛盾や購入者にとってリスクとなり得る契約、支払い、登記のプロセスを指摘している。

第4章では、明らかにした前売り販売システムを法的、組織的、技術的観点から評価するとともに、情報の非対称性に基づく経済学的モデルを用いて評価している。法制度に対する評価においては、実行可能性、明確性、有効性の基準を設定し分析した結果、諸制度間で矛盾が生じていること、事業の財務的実現性に関する責任が不明確であること、事業の支出管理のチェックが曖昧であること等を指摘している。組織的評価においては、事業関係者間の協力体制に対して、コミュニケーションの有効性、協力性の基準を設定し分析した結果、行政組織内の異なる部署間において複雑な手続きが発生していること、事業に関する情報提供に対して官僚的な手続きが生じていること、事業をチェックする第三者機関の関与が弱いことにより事業の中止や延期に対するリスクや購入者の資金の流用のリスクが高いこと等を示している。また、技術的評価においては、事業関係者間のコミュニケーションを維持するためのインフラの実行可能性と事業を遂行する人的資源に対する専門性の基準を設定して分析した結果、事業に関するデータや情報提供のためのインフラのシステムが複雑で利用しにくいことや市の建設課で実施されている事業の財務的実現性のチェックが非専門家により行われていること等を指摘している。

さらに、Chanらの開発したモデルを拡張し、情報の非対称性を考慮した経済学的分析も実施している。その結果、情報の非対称性が大きくなるほど不動産価格が高くなること、資金の流用が大きくなるほど前売り市場が大きくなり、事業の中止の可能性が高くなること等を示している。また、開発事業者の評判が不動産の前売り取引とその市場に大きな影響を及ぼすことや、金融機関には購入者の資金を流用することにおいて開発事業者と共謀するインセンティブが働くこと等を理論的に示している。これらの結果は、ホーチミン市における不動産の前売り販売取引の実態調査においても、一部確認されている。

第5章は、結論であり、本研究で得られた成果を取り纏めるとともに、国内外の経験に基づきベトナムの前売り販売手続きの改善方策を示し、今後の課題を提示している。不動産の前売り販売取引における情報の非対称性によるリスクを低減するためには、政府、開発事業者および購入者それぞれが、そのシステム改善のための取組みを行う必要がある。

本研究は、ベトナム国のように移行経済下で制度が未成熟な国おいて、情報の非対称性の影響を大きく受ける不動産の前売り販売取引の手続き過程の詳細を現地調査により明らかにするとともに、購入者のリスクの観点からそのシステムを法的、組織的、技術的、経済学的に分析、評価を行い、改善の方向性を示唆したものであり、社会的に価値の高い成果を挙げたものと評価できる。

よって、本論文は博士(工学)の学位請求論文として合格と認められる。