Publication Type

Journal Article

Version

publishedVersion

Publication Date

1-2020

Abstract

In analyzing regulatory experiments, a fundamental assumption is that the control group is unaffected. However, in many settings, this assumption may not hold. Generally, the total effect of a regulatory change consists of direct and indirect effects, but the standard difference-in-difference approach measures only direct effects. We apply our methods to the 2007 repeal of the uptick rule by the SEC. The indirect effects are substantial, because unlike the 2005 partial repeal, total repeal enables aggressive portfolio shorting. In particular, we find that short sellers become much more aggressive across the board, and shorting activity increases, even in control stocks where the uptick rule was already suspended. The 2007 repeal also causes increased price efficiency and slightly worse liquidity. We conclude that regulatory pilot designers should carefully consider potential spillovers.

Keywords

Inference, Short sales, Short interest, Tick test, Regulation SHO

Discipline

Finance and Financial Management

Research Areas

Finance

Publication

Journal of Financial Economics

Volume

135

Issue

1

First Page

68

Last Page

87

ISSN

0304-405X

Identifier

10.1016/j.jfineco.2019.05.016

Publisher

Elsevier

Copyright Owner and License

Publisher

Additional URL

https://doi.org/10.1016/j.jfineco.2019.05.016

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