Standard & Poor’s said Thursday that it has raised its credit ratings for three major Japanese securities houses as a result of their restructuring efforts.

S&P upgraded its long-term counterparty credit ratings for both Nomura Securities Co. and Daiwa Securities SB Capital Markets Co. to BBB plus from BBB.

The major U.S. credit-rating agency also raised its long-term counterparty credit rating for Nikko Securities Co. to BBB plus from BBB minus, and raised its short-term counterparty credit rating to A-2 from A-3.

The alteration to Nomura’s rating reflects the company’s cost cutting and other restructuring efforts, which should improve its ability to withstand capital market fluctuations in the future, S&P said.

Daiwa has improved its ability to cope with such fluctuations as it has changed its cost structure by introducing a performance-based salary system.

S&P also said Nikko is benefiting from its tieup with Citigroup Inc. of the United States while reducing fixed costs and lowering exposure to activities unrelated to its core business.