Portfolio Pumping and Managerial Structure
研究发现，美国股票型共同基金中，单人管理的基金在季度末和年末通过非法交易抬高回报的现象比团队管理的基金更严重，团队规模越大操纵越少，这主要源于团队内部的同伴效应。
Abstract Using U.S. equity mutual fund data, we show that portfolio pumping—an illegal trading activity that artificially inflates year- and quarter-end portfolio returns—is more pronounced among single-managed funds compared with team-managed ones. The return inflation by team-managed funds is 45% lower than by single-managed funds at year-ends. Also, portfolio pumping decreases as team size increases. These results are driven by peer effects among teams and, sometimes, amplified by less convex flow-performance relation in team-managed funds. Our findings are robust to differences in fund governance, manager career concerns, local networks, fund family policies, and changes in the SEC’s enforcement policies.