Short sellers placed fewer bearish bets on Standard & Poor’s 500 companies between April 30 and May 15 as the index rose 37 percent between March 9 and May 8, Bloomberg reported.

Des Moines-based Principal Financial Group Inc. led the way among financial institutions with a 40 percent decrease in short-term bets that its stock would fall. Financial institutions overall experienced a 3.2 percent decrease in short selling to 3.37 billion shares.

Shares among all companies in the S&P 500 that investors borrowed and sold short fell 1.7 percent to 9.87 billion in the two-week period, the lowest level since Feb. 27 and the third consecutive two-week stretch of declines.

Technology companies experienced the biggest decline in short interest as investors reduced bets against Microsoft Corp. and Cisco Systems Inc. by more than 25 percent.

Short selling is the sale of borrowed stock with the hope of buying it back at a lower price. The U.S. stock exchanges release data on the practice every two weeks.