In the month ended July 15, uncovered short positions totaled 2.17 billion shares, compared with 2.09 billion in the previous month.

Short positions in Worldcom totaled 137.2 million shares, up 20.2 million shares.

The previous record was set in the monthlong period ended Sept. 15, when open positions on short sales of active issues totaled 307.1 million shares.

For the comparable period a year ago, ended Feb. 13, 1987, open positions totaled 448.2 million shares.

For the month ended June 15, uncovered short positions totaled about 1.86 billion shares, compared with about 1.82 billion the previous month.

In the period ended Feb. 15, uncovered short positions totaled 1.81 billion shares, down from 1.87 billion shares the previous month.

In the month ended July 15, uncovered short positions totaled 1.10 billion shares, up from 1.08 billion in the previous month.

For the month ended June 15, uncovered short positions totaled 1.08 billion shares in 5,378 stocks.

In the previous four weeks, ended Aug. 15, open positions on short sales of active issues totaled 299.5 million shares.

The short positions in 5,328 stocks on the Nasdaq market totaled 1.02 billion shares.