BENGALURU, Sept 30 (Reuters) - Indian shares jumped nearly 2% on Friday, boosted by banks and metal stocks, after the country's central bank hiked its key policy rate for the fourth straight time as expected to bring down persistently high inflation.

The NSE Nifty 50 index rose 1.93 to 17,138, as of 0834 GMT, and the S&P BSE Sensex gained 2% to 56,935. Both the indexes posted their biggest jump in a month, breaking a seven-day losing streak.

The Nifty and the Sensex are up more than 8% so far this quarter, if gains hold, set for their best quarter in a year.

The Reserve Bank of India (RBI) has now raised interest rates by a total 190 basis points since its first unscheduled mid-meeting hike in May but inflation continues to remain stubbornly high - a phenomenon that is affecting much of the global economy.

"The fact that there were no negative surprises is what is positive for the markets. It is also positive that the inflation expectation has been maintained," said Hemali Dhame, associate vice-president, research, Kotak Securities Ltd.

The rate sensitive Nifty bank index rose 3%, while the financials gained 2.7% and metals added 2.8%.

"The banking sector is going to do well fundamentally on its own. Their credit growth is strong ... If there is sufficient liquidity then the banks will not have to aggressively raise deposit rates, which means they can see a margin expansion in the near term," Dhame said.

Shares of Hindalco Industries, up 6.1%, was the Nifty 50 index's top gainer.

The RBI, which has spent massive forex reserves to arrest the currency's fall against the strong U.S. dollar, said the context of adequacy of foreign exchange reserves is always kept in mind while intervening.

The RBI signalled that foreign exchange interventions are likely to continue to defend any extreme volatility in the rupee, said Sakshi Gupta, principal economist at HDFC Bank. (Reporting by Rama Venkat and Nallur Sethuraman in Bengaluru; Editing by Dhanya Ann Thoppil, Savio D'Souza and Rashmi Aich)