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Experimental results of a study of wind waves in the Gulf Stream frontal zone are presented. Measurements of two‐dimensional radar spectra of surface waves and surface current were performed during ship crossings of the Gulf Stream under different wind conditions. Waves reflected from the Gulf Stream were observed on the windward side for an along current wind. These effects resulted in a widening of the spectrum angular distribution and a deviation of the mean wave direction from that of the wind. Trapped waves were observed under against current winds. Depending on wave age, the trapped waves were either locally generated (developing waves) or entered into the jet downstream (nearly fully developed waves). Trapped waves significantly increased the wave energy locally. The experimental data are interpreted in terms of wave kinematics and the equation of spectrum evolution in the relaxation approximation.

Investment managers often manage a portfolio with respect to a benchmark. Typically, they use a mean‐variance optimization framework to maximize the information ratio of their portfolio. We develop an unconventional approach to this question. Given a set of assumptions, we ask what optimal percentage of the benchmark stocks the portfolio manager should select. This optimal portfolio depends on Fisher's and Wallenius's noncentral hypergeometric distributions. We find that the optimal selectivity of a benchmark universe varies from 50% to 80%. These results are provocative, given that many enhanced index portfolio managers select a low percentage of the benchmark universe.

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