Mumbai: New India Assurance, having surged 50% in the past five trading sessions, has opted for an annual revision of health insurance premiums, moving away from the previous practice of increasing tariffs every three years. Shares of New India Assurance gained 10% in Thursday's session to Rs 255.85 on the Bombay Stock Exchange, when the index rose 0.13%.After a 25-30% increase in retail health insurance premiums in June, the first in six years, the company, initially slated for revisions in 2020 after a three-year gap, deferred its decision due to the pandemic.