LONDON Moodys has maintained its credit rating B3 for Pakistan and urged the government for improving tax collection besides cutting down its expenses, a senior analyst from the ratings agency told on Monday. According to media reports, Moodys investors services analyst Aninda Mitra said that improvement in balance of payments is helpful in maintaining B3 stable outlook, adding that it is also vital to improve revenue collection besides cutting down expenses. He further said that implementation on the measures to control fiscal deficit would also be helpful in credit rating.