Multiple Priors And No-Transaction Region

We study single period asset allocation problems of the investor who maximizes the expected utility with respect to non-additive beliefs. The non-additive beliefs of the investor model the presence of an uncertainty and they are assumed to be consistent with the Maxmin expected utility theory of Gilboa and Schmeidler (1989). The proportional transaction costs are incorporated into the model. We provide the explicit form solutions for the bounds of no-transaction regions which completely determine the optimal policy of the investor. --uncertainty modelling,utility theory,maxmin portfolio selection,transaction costs

Firms' investment under financing constraints. An euro area investigation

In this paper we describe a theoretical model of optimal investment of various types of financially constrained firms. We show that the resulting relationship between internal funds and investment is non-monotonic. In particular, the magnitude of the cash flow sensitivity of the investment is lower for firms with credit rationing compared to firms that are able to obtain short-term external financing. The inverse relationship is driven by the leverage multiplier effect. A positive cash flow shock increases the short-term borrowing capacity of the firm, which in turn has a positive effect on investment and firm's growth. Moreover, the leverage multiplier effect is the highest for firms relying on short-term credits and it is lower for firms that are able to obtain long-term financing. Analysing a large euro area data set we find strong empirical support for our theoretical predictions. The results also help to explain some contradictory findings in the financing constraints literature.Financing constraints, growth, investment, cash flow sensitivity

Spurious regressions of stationary AR(p) processes with structural breaks

When a pair of independent series is highly persistent, there is a spurious regression bias in a regression between these series, closely related to the classic studies of Granger and Newbold (1974). Although this is well known to occur with independent I(1) processes, this paper provides theoretical and numerical evidence that the phenomenon of spurious regression also arises in regressions between stationary AR(p) processes with structural breaks, which occur at different points in time, in the means and the trends. The intuition behind this is that structural breaks can increase the persistence levels in the processes (e.g., Granger and Hyung (2004)), which then leads to spurious regressions. These phenomena occur for general distributions and serial dependence of the innovation terms

Multiple priors and no-transaction region

We study single period asset allocation problems of the investor who maximizes the expected utility with respect to non-additive beliefs. The non-additive beliefs of the investor model the presence of an uncertainty and they are assumed to be consistent with the Maxmin expected utility theory of Gilboa and Schmeidler (1989). The proportional transaction costs are incorporated into the model. We provide the explicit form solutions for the bounds of no-transaction regions which completely determine the optimal policy of the investor

Non-additive anonymous games

This paper introduces a class of non-additive anonymous games where agents are assumed to be uncertain (in the sense of Knight) about opponents’ strategies and about the initial distribution over players’ characteristics in the game. These uncertainties are modelled by non-additive measures or capacities. The Cournot-Nash equilibrium existence theorem is proven for this class of games. It is shown that the equilibrium distribution can be symmetrized under milder conditions than in the case of additive games. In particular, it is not required for the space characteristics to be atomless under capacities. The set-valued map of the Cournot-Nash equilibria is upper-semicontinuous as a function of initial beliefs of the players for non-additive anonymous games

On uncertainty, market timing and the predictability of tick by tick exchange rates

This paper examines the predictability of exchange rates on a transaction level basis using both past transaction prices and the structure of the order book. In contrast to the existing literature we also recognise that the trader may be subject to (Knightian) uncertainty as opposed to risk regarding the structure by which exchange rates are determined and hence regarding both the model he employs to make predictions and the reliability of any conditioning information. The trader is faced with a two stage decision problem due to this uncertainty; first he needs to resolve a question of market timing as to when to enter the market and then secondly how to trade. We provide a formalisation for this two stage decision problem. Statistical tests indicate the significance of out of sample ability to predict directional changes and the economic value of predictability using one week of tick-by-tick data on the USD-DM exchange rate drawn from Reuters DM2002 electronic trading system. These conclusions rest critically on the frequency of trading which is controlled by an inertia parameter reflecting the degree of uncertainty; trading too frequently significantly reduces profitability taking account of transaction costs

Short selling and price discovery in corporate bonds

We show short selling in corporate bonds forecasts future bond returns. Short selling predicts bond returns where private information is more likely, in high-yield bonds, particularly after Lehman’s collapse. Short selling predicts returns following both high and low past bond returns. This, together with short selling increasing following past buying order imbalances, suggests short sellers trade against price pressures as well as trade on information. Short selling predicts bond returns both in the individual bonds that are shorted and in other bonds by the same issuer. Past stock returns and short selling in stocks predict bond returns, but do not eliminate bond short selling predicting bond returns. Bond short selling does not predict the issuer’s stock returns. These results show bond short sellers contribute to efficient bond prices and that short sellers’ information flows from stocks to bonds, but not from bonds to stocks

Toxic arbitrage

Short-lived arbitrage opportunities arise when prices adjust with a lag to new information. They are toxic because they expose dealers to the risk of trading at stale quotes. Hence, theory implies that more frequent toxic arbitrage opportunities and faster responses to these opportunities should impair liquidity. We provide supporting evidence using data on triangular arbitrage. As predicted, illiquidity is higher on days when the fraction of toxic arbitrage opportunities and arbitrageurs’ relative speed are higher. Overall, our findings suggest that the price efficiency gain of high-frequency arbitrage comes at the cost of increased adverse selection risk