(Updates to add NYSE short interest figures)

 
    DOW JONES NEWSWIRES 
 

Short selling rose at the New York Stock Exchange and Nasdaq during the first half of August as markets continued to rally.

The increases reversed declines in the second half of July, when Nasdaq's twice-a-month statistic fell slightly for the first time since the first half of May.

For the period ended Aug. 14, the number of short-selling positions at the NYSE not yet closed out, known as short interest, rose 1.3%. The positions stood at 14,196,401,372 shares from a revised 14,019,075,490 shares in the period ended July 31.

Of all 2,906 Nasdaq securities, short interest rose to 6.8 billion shares as of Aug. 14, compared with 2,903 issues and 6.78 billion shares in the last period.

The latest figure equals just under three days of average volume, compared with 3.1 days in the prior period. That measurement fell because overall trading volume has been rising.

Investors who short shares borrow and sell them, betting that prices will fall so they can buy them back at a lower price for return to the lender. Stocks can also be shorted for reasons other than bearish bets, including hedging strategies.

In July, the Securities and Exchange Commission issued new rules to govern short selling, promising investors new information about the volume and velocity of negative bets placed against companies. The move, which doesn't impose strong new curbs on short selling beyond those imposed last fall, comes amid political pressure to reduce abusive short selling.

-By Alexandra Scaggs and Kathy Shwiff, Dow Jones Newswires; 212-416-2673; alexandra.scaggs@dowjones.com