The tide is turning in the market for speculative-grade loans as investors refuse to buy some deals deemed too risky.

Rocket Software Inc. pulled $725 million of loans from the market this week that would have refinanced debt and paid for a dividend to its co-founders and private-equity firm Court Square Capital Partners LP, according to data compiled by Bloomberg. The deal is at least the third to be withdrawn in the last month, with cable TV provider WideOpenWest Finance LLC canceling $1.97 billion in loans and Dutch LLC, which does business as women's apparel company Joie, scrapping a $200 million debt offering.

The loan market is starting to show signs of tightening more than six months after the Federal Reserve and Office of the Comptroller of the Currency sent letters to banks telling them to improve their deteriorating underwriting standards. Investors are demanding better terms and pulled cash from leveraged-loan funds the last two weeks, snapping an unprecedented 95 straight weeks of inflows.