How to deal with real estate booms: Lessons from country experiences

The financial crisis showed, once again, that neglecting real estate booms can have disastrous consequences. In this paper, we spell out the circumstances under which a more active policy agenda on this front would be justified. Then, we offer insights on the pros and cons as well as implementation challenges of various policy tools that can be used to contain the damage to the financial system and the economy from real estate boom–bust episodes. These insights derive from econometric analysis, when possible, and case studies of country experiences. Broadly, booms financed through credit and involving leverage are more likely to warrant a policy response. In that context, macroprudential measures can be targeted more precisely to specific sources of risk, but they may prove ineffective because of circumvention. In that case, monetary policy may have to be used to lean against the wind.     

Positive return premia in Japan

This paper examines Jensen's [J. Finance, 1968, 23, 389–416] alphas and the time-varying return premia unexplained by standard risk factors in Japan and presents several new findings. First, in contrast to the US experience, positive alphas remain after Fama and French's three factors are applied to excess stock returns in Japan. Second, positive alphas remain in Japan, even if the Fama–French three factors combined with momentum and reversal factors are applied to excess stock returns. Third, the positive return premia unexplained by these five factors bear little relation to the dynamics of the Japanese macroeconomy. Fourth, the time series evolution of the positive return premia indicates autonomous dynamics with at least three regimes. Fifth, we can predict or time the acquisition of the positive return premia for small-size portfolios in Japan by observing the direction and effect of the return premia of large-size portfolios and high-book equity to market equity (BE/ME) portfolios. Finally, application of the self-exciting threshold autoregressive (SETAR) model shows that the size effects are stronger than the BE/ME effects in Japan, given that the return premia from small-size portfolios in the SETAR model are bounded by positive thresholds, while the return premia from high-BE/ME portfolios are bounded by negative thresholds.     

The affine Heston model with correlated Gaussian interest rates for pricing hybrid derivatives

In this article we define a multi-factor equity–interest rate hybrid model with non-zero correlation between the stock and interest rate. The equity part is modeled by the Heston model and we use a Gaussian multi-factor short-rate process. By construction, the model fits in the framework of affine diffusion processes, allowing fast calibration to plain vanilla options. We also provide an efficient Monte Carlo simulation scheme.     

Portfolio optimization under model uncertainty and BSDE games

We consider robust optimal portfolio problems for markets modeled by (possibly non-Markovian) Itô–Lévy processes. Mathematically, the situation can be described as a stochastic differential game, where one of the players (the agent) is trying to find the portfolio that maximizes the utility of her terminal wealth, while the other player (“the market”) is controlling some of the unknown parameters of the market (e.g., the underlying probability measure, representing a model uncertainty problem) and is trying to minimize this maximal utility of the agent. This leads to a worst case scenario control problem for the agent. In the Markovian case, such problems can be studied using the Hamilton–Jacobi–Bellman–Isaacs (HJBI) equation, but these methods do not work in the non-Markovian case. We approach the problem by transforming it into a stochastic differential game for backward stochastic differential equations (a BSDE game). Using comparison theorems for BSDEs with jumps we arrive at criteria for the solution of such games in the form of a kind of non-Markovian analogue of the HJBI equation. The results are illustrated by examples.     

Derivatives pricing with marked point processes using tick-by-tick data

I propose to model stock price tick-by-tick data via a non-explosive marked point process. The arrival of trades is driven by a counting process in which the waiting time between trades possesses a Mittag–Leffler survival function and price revisions have an infinitely divisible distribution. I show that the partial-integro-differential equation satisfied by the value of European-style derivatives contains a non-local operator in time-to-maturity known as the Caputo fractional derivative. Numerical examples are provided for a marked point process with conditionally Gaussian and with conditionally CGMY price innovations. Furthermore, the infinitesimal generator of the marked point process derived to price derivatives coincides with that of a Lévy process of either finite or infinite activity.     

Conflicts of interest and agent heterogeneity in buyer brokerage

This article investigates the incentives of agents working with buyers (buying agents) under the fixed percentage commission system and the implications on housing market outcomes. Our model shows that the absence of a binding contract creates a risk of losing clients for buying agents, which helps mitigate the conflict of interest between buying agents and their clients. Both the buying agent's prediction accuracy regarding their client's reservation prices and the level of tolerance given by the buyer to the buying agent affect the binding force. Results from simulations and empirical analyses using house transactions in Canada support our model predictions.     

Unbundling tolls from contracts: a new road PPP model

Considerable evidence from different countries has revealed important shortcomings in most road public–private partnership (PPP) models. In this paper a new PPP model is presented that overcomes some of the problems found in PPP road contracts. The new model is based on separating user tolls from the fees paid to PPP contractors and setting up new institutional arrangements to oversee PPPs.     

A missing link in modeling : The future of time-use as an illustration

A Theory of Action is formulated based on the intentionality of actions. The transformation rules from the new theory to system dynamics were developed and the methodology was then applied to certain problems of future time-use. The modeling approach used is holistic and it requires a meta-system to system dynamics in order to produce quantitative results.