Modelos baseados em agentes aplicados à dinâmica de preços do mercado imobiliário

Um dos aspectos regulatórios fundamentais para o mercado imobiliário no Brasil são os limites para obtenção de financiamento no Sistema Financeiro de Habitação. Esses limites podem ser definidos de forma a aumentar ou reduzir a oferta de crédito neste mercado, alterando o comportamento dos seus agentes e, com isso, o preço de mercado dos imóveis. Neste trabalho, propomos um modelo de formação de preços no mercado imobiliário brasileiro com base no comportamento dos agentes que o compõem. Os agentes vendedores têm comportamento heterogêneo e são influenciados pela demanda histórica, enquanto que os agentes compradores têm o seu comportamento determinado pela disponibilidade de crédito. Esta disponibilidade de crédito, por sua vez, é definida pelos limites para concessão de financiamento no Sistema Financeiro de Habitação. Verificamos que o processo markoviano que descreve preço de mercado converge para um sistema dinâmico determinístico quando o número de agentes aumenta, e analisamos o comportamento deste sistema dinâmico. Mostramos qual é a família de variáveis aleatórias que representa o comportamento dos agentes vendedores de forma que o sistema apresente um preço de equilíbrio não trivial, condizente com a realidade. Verificamos ainda que o preço de equilíbrio depende não só das regras de concessão de financiamento no Sistema Financeiro de Habitação, como também do preço de reserva dos compradores e da memória e da sensibilidade dos vendedores a alterações na demanda. A memória e a sensibilidade dos vendedores podem levar a oscilações de preços acima ou abaixo do preço de equilíbrio (típicas de processos de formação de bolhas); ou até mesmo a uma bifurcação de Neimark-Sacker, quando o sistema apresenta dinâmica oscilatória estável.

Fail-Safe Testing of Web Applications

This dissertation introduces an approach to generate tests to test fail-safe behavior for web applications. We apply the approach to a commercial web application. We build models for both behavioral and mitigation requirements. We create mitigation tests from an existing functional black box test suite by determining failure type and points of failure in the test suite and weaving required mitigation based on weaving rules to generate a test suite that tests proper mitigation of failures. A genetic algorithm (GA) is used to determine points of failure and type of failure that needs to be tested. Mitigation test paths are woven into the behavioral test at the point of failure based on failure specific weaving rules. A simulator was developed to evaluate choice of parameters for the genetic algorithm. We showed how to tune the fitness function and performed tuning experiments for GA to determine what values to use for exploration weight and prospecting weight. We found that higher defect densities make prospecting and mining more successful, while lower mitigation defect densities need more exploration. We compare efficiency and effectiveness of the approach. First, the GA approach is compared to random selection. The results show that the GA performance was better than random selection and that the approach was robust when the search space increased. Second, we compare the GA against four coverage criteria. The results of comparison show that test requirements generated by a genetic algorithm (GA) are more efficient than three of the four coverage criteria for large search spaces. They are equally effective. For small search spaces, the genetic algorithm is less effective than three of the four coverage criteria. The fourth coverage criteria is too weak and unable to find all defects in almost all cases. We also present a large case study of a mortgage system at one of our industrial partners and show how we formalize the approach. We evaluate the use of a GA to create test requirements. The evaluation includes choice of initial population, multiplicity of runs and a discussion of the cost of evaluating fitness. Finally, we build a selective regression testing approach based on types of changes (add, delete, or modify) that could occur in the behavioral model, the fault model, the mitigation models, the weaving rules, and the state-event matrix. We provide a systematic method by showing the formalization steps for each type of change to the various models.

Comment on Rule 14a-8(i)(9), Securities and Exchange Commission, June 30, 2015

The Securities and Exchange Commission has been analyzing its interpretation under Subsection (i)(9) of Rule 14a-8. This provision allows for the exclusion of shareholder proposals that conflict with those submitted by management. The staff has been examining its interpretation since instructed to do so by the chair of the SEC following a no action appeal in a case involving Whole Foods. A number of letters and memos submitted in connection with the review have analyzed the issue. At least one asserted that any change in interpretation required the Commission to go through the process of notice and comment. This letter asserts that notice and comment is not required, relying extensively on Perez v. Mortgage Bankers Association.

Bank bonus compromise bodes ill for the Single Supervisory Mechanism. CEPS Commentary, 8 March 2013

The European Parliament has probably won a Pyrrhic victory with its position on bank bonuses, argues CEPS CEO Karel Lannoo in this new Commentary. In return, EU member states got what they wanted with the new Capital Requirements Directive (CRD IV): no binding leverage ratio; mortgage risk weightings and capital add-ons to be determined by member states; and no obligatory consolidated capital position for bank-insurance companies. In other words, Banking Union will start out with capital rules that are more like Emmental cheese than a single rulebook. This is a huge encumbrance for a well-functioning Single Supervisory Mechanism (SSM), and makes a single resolution mechanism impossible.

The distribution of debt across euro area countries : The role of individual characteristics, institutions and credit conditions. National Bank of Belgium Working Paper No. 252, December 2013

The aim of this paper is twofold. First, we present an up-to-date assessment of the differences across euro area countries in the distributions of various measures of debt conditional on household characteristics. We consider three different outcomes: the probability of holding debt, the amount of debt held and, in the case of secured debt, the interest rate paid on the main mortgage. Second, we examine the role of legal and economic institutions in accounting for these differences. We use data from the first wave of a new survey of household finances, the Household Finance and Consumption Survey, to achieve these aims. We find that the patterns of secured and unsecured debt outcomes vary markedly across countries. Among all the institutions considered, the length of asset repossession periods best accounts for the features of the distribution of secured debt. In countries with longer repossession periods, the fraction of people who borrow is smaller, the youngest group of households borrow lower amounts (conditional on borrowing), and the mortgage interest rates paid by low-income households are higher. Regulatory loan-to-value ratios, the taxation of mortgages and the prevalence of interest-only or fixed-rate mortgages deliver less robust results.

Asset-backed securities: The key to unlocking Europe's credit markets? Bruegel Policy Contribution 2014/07, 24 July 2014

The European market for asset-backed securities (ABS) has all but closed for business since the start of the economic and financial crisis. ABS (see Box 1) were in fact the first financial assets hit at the onset of the crisis in 2008. The subprime mortgage meltdown caused a deterioration in the quality of collateral in the ABS market in the United States, which in turn dried up overall liquidity because ABS AAA notes were popular collateral for inter-bank lending. The lack of demand for these products, together with the Great Recession in 2009, had a considerable negative impact on the European ABS market. The post-crisis regulatory environment has further undermined the market. The practice of slicing and dicing of loans into ABS packages was blamed for starting and spreading the crisis through the global financial system. Regulation in the post-crisis context has thus been relatively unfavourable to these types of instruments, with heightened capital requirements now necessary for the issuance of new ABS products. And yet policymakers have recently underlined the need to revitalise the ABS market as a tool to improve credit market conditions in the euro area and to enhance transmission of monetary policy. In particular, the European Central Bank and the Bank of England have jointly emphasised that: “a market for prudently designed ABS has the potential to improve the efficiency of resource allocation in the economy and to allow for better risk sharing... by transforming relatively illiquid assets into more liquid securities. These can then be sold to investors thereby allowing originators to obtain funding and, potentially, transfer part of the underlying risk, while investors in such securities can diversify their portfolios... . This can lead to lower costs of capital, higher economic growth and a broader distribution of risk” (ECB and Bank of England, 2014a). In addition, consideration has started to be given to the extent to which ABS products could become the target of explicit monetary policy operations, a line of action proposed by Claeys et al (2014). The ECB has officially announced the start of preparatory work related to possible outright purchases of selected ABS1. In this paper we discuss how a revamped market for corporate loans securitised via ABS products, and how use of ABS as a monetary policy instrument, can indeed play a role in revitalising Europe’s credit market. However, before using this instrument a number of issues should be addressed: First, the European ABS market has significantly contracted since the crisis. Hence it needs to be revamped through appropriate regulation if securitisation is to play a role in improving the efficiency of resource allocation in the economy. Second, even assuming that this market can expand again, the European ABS market is heterogeneous: lending criteria are different in different countries and banking institutions and the rating methodologies to assess the quality of the borrowers have to take these differences into account. One further element of differentiation is default law, which is specific to national jurisdictions in the euro area. Therefore, the pool of loans will not only be different in terms of the macro risks related to each country of origination (which is a ‘positive’ idiosyncratic risk, because it enables a portfolio manager to differentiate), but also in terms of the normative side, in case of default. The latter introduces uncertainties and inefficiencies in the ABS market that could create arbitrage opportunities. It is also unclear to what extent a direct purchase of these securities by the ECB might have an impact on the credit market. This will depend on, for example, the type of securities targeted in terms of the underlying assets that would be considered as eligible for inclusion (such as loans to small and medium-sized companies, car loans, leases, residential and commercial mortgages). The timing of a possible move by the ECB is also an issue; immediate action would take place in the context of relatively limited market volumes, while if the ECB waits, it might have access to a larger market, provided steps are taken in the next few months to revamp the market. We start by discussing the first of these issues – the size of the EU ABS market. We estimate how much this market could be worth if some specific measures are implemented. We then discuss the different options available to the ECB should they decide to intervene in the EU ABS market. We include a preliminary list of regulatory steps that could be taken to homogenise asset-backed securities in the euro area. We conclude with our recommended course of action.

Seguro hipotecario /

Mode of access: Internet.

HUD guarantee of tax-exempt hospital financing : hearing before the Subcommittee on Housing and Community Development of the Committee on Banking, Finance, and Urban Affairs, House of Representatives, Ninety-sixth Congress, first session, May 17, 1979.

"Serial no. 96-21."

Shopping for your loan : 33 answers.

Shipping list no.: 2011-0389-P.

Housing finance institutions abroad : a directory.

"HUD-548-1A"--P. [4] of cover.

Privilèges du crédit foncier de France; leur étendue depuis la fin de son monopole. Obligations foncières ou lettres de gage, leur caractère hypothécaire.

Mode of access: Internet.

The Federal home loan banks in the housing finance system.

"July 1993"--Cover.

Home equity conversion mortgages : program participants.

Mode of access: Internet.

Proceedings, reverse mortgages : improving housing market liquidity ; March 2, 1993 /

Mode of access: Internet.

The ... baseline environmental management report.

Title from cover.