Nomura Holdings Inc.'s credit rating was raised by Moody's Investors Service for the first time since November 2005 as Japan's largest brokerage showed improved profitability.

The company's long-term rating was increased by two levels to Baa1 from the lowest investment grade of Baa3, Moody's said in a statement Wednesday. Nomura's capitalization had benefited from a cost-reduction program and lower holdings of illiquid assets, the agency said.

The move follows the ratings company's two downgrades of Nomura since 2009, when securities firms worldwide were roiled by the global financial crisis. Chief Executive Officer Koji Nagai has pared expenses and overseen a profit resurgence since he took the post in August 2012, although earnings growth has stalled this year as waning demand for Japanese stocks erodes brokerage commissions.