UPDATE 1-Nasdaq, NYSE short interest near flat in late April

* NYSE short interest falls 0.4 pct

* Nasdaq short interest up 0.08 pct

* For Reuters Factboxes on shorted stocks, see [ID:nN11268727] and [ID:nN11116861]

NEW YORK, May 11 (Reuters) - Short interest on the New York Stock Exchange and the Nasdaq were little changed in late April during a time when the S&P 500 hit a 19-month high, data showed on Tuesday.

Short interest on the New York Stock Exchange fell 0.36 percent in the second half of April, while it edged up 0.08 percent on the Nasdaq, the exchanges said on Tuesday.

Many investors see short interest as an important indicator of market sentiment. A rise in the number of investors betting shares will fall can indicate that market sentiment is turning bearish.

As of April 30, short interest on the NYSE fell to about 13.84 billion shares from 13.89 billion shares for the first half of April. On Nasdaq, short interest rose to about 7.081 billion shares as of April 30 from 7.076 billion shares in the first half of the month.

The fall in NYSE short interest, though small, represents the third straight decline since mid-March. During that time, short interest on the NYSE has fallen 2 percent.

Conversely, short interest on Nasdaq has risen for the last three biweekly periods. Over that timeframe, it has risen 1.7 percent.

The Nasdaq said the short interest represents 2.20 days’ average daily volume in the current period, compared to an average of 2.21 days for the previous period. On NYSE, short interest on April 30 was equal to 3.62 percent of the total shares outstanding.

Investors who sell securities short seek to profit from bets the stocks will fall. They borrow shares and sell them, with the hope of buying back and returning the shares at a lower price, pocketing the difference.