Robust profit opportunities in risky financial portfolios

Cataloged from PDF version of article.For risky financial securities with given expected return vector and covariance matrix, we propose the concept of a robust profit opportunity in single- and multiple-period settings. We show that the problem of finding the “most robust” profit opportunity can be solved as a convex quadratic programming problem, and investigate its relation to the Sharpe ratio. © 2004 Elsevier B.V. All rights reserved

Corporate Control, Portfolio Choice, and the Decline of Banking

The authors focus on the persistence of bank unprofitability during the 1980s. A large literature in banking, following Merton (1977), concentrates on the incentives of shareholders to maximize the value of the (fixed rate) deposit insurance subsidy provided by the government by taking on risk inefficiently, so called moral hazard' risk. This paper takes issue with this moral hazard explanation for the performance of the banking industry. The moral hazard view assumes that shareholders make the lending decisions and can take on risk to maximize the value of insurance if they desire. The authors assume bank managers, who may own a fraction of the bank, make the lending decisions. If managers have different objectives than outside shareholders and disciplining in managers is costly, then managerial decisions may be at odds with the decisions outside shareholders would like them to take. When investment opportunities are declining, managers behave differently than in healthy' industries. This is particularly true in banking, where asymmetric information and deposit insurance allow banks resources to invest even if there are few good lending opportunities. The risk-avoiding behavior of managers stressed in the corporate finance literature presumes that conservative behavior is sufficient for job and perquisite preservation. When bad managers predominate, conservative behavior may not allow most managers to keep their jobs and perquisites. These managers may find it optimal to take excessively risky actions. The paper sets out a game between a bank manager and shareholders and solves for a sequential Nash equilibrium. A bank manager chooses either risky or safe loans based on the quality of the loan opportunities available to the manager (the manager s type). The choice of loan portfolios is observed by shareholders, but the manager s type is not. If the manager is fired, shareholders decide whether to invest in new bank assets (hire a new manager) or move their capital out of banking (liquidate capital). In any period that they are employed, managers receive a private benefit. Using data on the equity ownership structure of large bank holding companies, the authors test the predictions of the corporate control model of banking against an alternative model based on moral hazard problems between banks and regulators. With respect to the choice of loans made, the authors findings are consistent with corporate control problems playing an important role, but are inconsistent with moral hazard playing a dominant role in banking. None of the results are what a moral hazard model would predict. However, the analysis is done for adequately-capitalized banks. Thus, if the value of bank equity is low enough, the interests of inside and outside owners are aligned, so there are no corporate control problems of the sort modeled by the authors. It may be accurate to say that, for large U.S. banks, corporate control problems have been the cause of the conditions of which moral hazard may be an accurate characterization. The presence of agency costs suggests that the underlying trends that reduced profitability in the 1980s may persist, despite high bank earnings in the early 1990s. That banking is regulated does not appear to be a sufficient countervailing force. To the extent that chartered banks must transform themselves into nonbanks as they seek nonlending and deposit-taking activities which are profitable, the authors suggest that banking' is in decline. Their conclusions concern the difficulties that outside equityholders face during the transition period.

Market models with optimal arbitrage

We construct and study market models admitting optimal arbitrage. We say that a model admits optimal arbitrage if it is possible, in a zero-interest rate setting, starting with an initial wealth of 1 and using only positive portfolios, to superreplicate a constant c>1. The optimal arbitrage strategy is the strategy for which this constant has the highest possible value. Our definition of optimal arbitrage is similar to the one in Fernholz and Karatzas (2010), where optimal relative arbitrage with respect to the market portfolio is studied. In this work we present a systematic method to construct market models where the optimal arbitrage strategy exists and is known explicitly. We then develop several new examples of market models with arbitrage, which are based on economic agents' views concerning the impossibility of certain events rather than ad hoc constructions. We also explore the concept of fragility of arbitrage introduced in Guasoni and Rasonyi (2012), and provide new examples of arbitrage models which are not fragile in this sense

Theory and Applications of Robust Optimization

In this paper we survey the primary research, both theoretical and applied, in the area of Robust Optimization (RO). Our focus is on the computational attractiveness of RO approaches, as well as the modeling power and broad applicability of the methodology. In addition to surveying prominent theoretical results of RO, we also present some recent results linking RO to adaptable models for multi-stage decision-making problems. Finally, we highlight applications of RO across a wide spectrum of domains, including finance, statistics, learning, and various areas of engineering.Comment: 50 page

Risk overhang and loan portfolio decisions

Despite operating under substantial regulatory constraints, we find that commercial banks manage their investments largely consistent with the predictions of portfolio choice models with capital market imperfections. Based on 1990-2002 data for small (assets less than $1 billion) U.S. commercial banks, net new lending to the business, real estate, and consumer sectors increased with expected sector profitability, tended to decrease with the illiquidity of existing (overhanging) loan stocks, and was responsive to correlations in cross-sector returns. Small banks are most appropriate for this study, because they make illiquid loans and manage risk via on-balance sheet (non-hedged) diversification strategies.Portfolio management ; Investment banking

When bigger isn’t better : bailouts and bank behaviour

Lending retail deposits to SMEs and household borrowers may be the traditional role of commercial banks: but banking in Britain has been transformed by increasing consolidation and by the lure of high returns available from wholesale Investment activities. With appropriate changes to the baseline model of commercial banking in Allen and Gale (2007), we show how market power enables banks to collect „seigniorage‟; and how „tail risk‟ investment allows losses to be shifted onto the taxpayer. In principle, the high franchise values associated with market power assist regulatory capital requirements to check risk-taking. But when big banks act strategically, bailout expectations can undermine these disciplining devices: and the taxpayer ends up „on the hook‟- as in the recent crisis. That structural change is needed to prevent a repeat seems clear from the Vickers report, which proposes to protect the taxpayer by a „ring fence‟separating commercial and investment banking

Who Manages The Money? How Foundations Should Help Democratize Capital

For the past twenty-five years or more there has been a groundswell of activity among investment managers institutional investors, consultants and diversity advocates to democratize capital -- that is, to create more opportunities for diverse investment professionals and the firms they lead, to manage institutional capital This effort, grounded in both fiduciary and equity principles, has led to the growth of many diverse investment management firms like Progress Investment Management Company LLC ("Progress") and others. A range of stakeholders now recognizes that democratization of capital brings a range of positive benefits to our industry and society at larg

Awareness and Stock Market Participation

The extent to which consumers are aware of available financial assets depends on the incentives of asset suppliers to spread information about the instruments they issue. We propose a theoretical framework in which the amount of information disseminated and the probability of individuals becoming aware of financial assets are correlated with the probability that, once informed, they will invest in the asset and negatively affected by the cost of spreading information. Social learning is a further channel through which potential investors may come to be informed about existing assets. While social learning may limit the production of financial information by assets suppliers, it increases the probability that individuals become financially aware. These predictions are supported by data on awareness of financial assets available in the 1995 and 1998 waves of the Italian Survey of Household Income and Wealth. Lack of financial awareness has important implications for understanding the stockholding puzzle and for estimating stock market participation costs.financial information, portfolio choice

The Power of Strategic Mission Investing

A growing number of foundations are offering low-interest loans, buying into green business ventures, and investing in other asset classes to advance their missions. Yet most mission investing remains haphazard and inconsequential. To bring about real change, foundations need to take a fundamentally different approach, making strategic mission investments that complement their grantmaking. Authors Mark Kramer and Sarah Cooch talk about strategic mission investing in the Fall 2007 issue of Stanford Social Innovation Review