Subject: File No. 4-581
From: Donald R. Davis, Ph.D.
Affiliation: Retired biochemist

September 5, 2009

The one change that I support is to enforce capital requirements throughout the trading day, not just at day's end. It is clearly wrong when traders flout the rules by taking huge intraday short positions that they cannot maintain overnight.

As SEC has previously concluded, there is no good evidence that any other changes in short-selling rules would be beneficial, despite the noisy claims to the contrary.