Mumbai, Jan 25 (Agencies): Trading sentiment turned bearish and the Bombay Stock Exchange benchmark Sensex fell 181.83 points to 18,969.45 on heavy selling in pivotals led by banks after the RBI increased key policy rates to a two-year high and revised upwards its inflation forecast.

Besides, investors unwound their pending positions in the derivatives segments ahead of the current month settlement expiry, and a weakening global trend.

Opening on a higher note, the gauge climbed to 19,340.99 before ending with losses as the Reserve Bank of India (RBI) raised the key lending and borrowing rates by 0.25 percentage points and forecast inflation at 7 per cent by March 31, higher than the earlier prediction of 5.5 per cent.

Similarly, the broad-based National Stock Exchange index Nifty lost 55.85 points to 5,687.40, after touching the day's high of 5,801.55, as the market remained under pressure following the seventh time hike in interest rates in a row within a year.

Barring Japan's Nikkei, Asian stock markets closed lower and a weak opening in Europe further dampened trading sentiment here.

Retail investors and funds indulged in squaring up their pending positions before the end of January settlement in the derivatives segment.

The banking sector index suffered the most by losing 2.34 per cent to 12,349.75 with most of the big lenders like State Bank of India, ICICI Bank and HDFC banks closed with losses despite their better performance in the third quarter.

Fast Moving Consumer Goods sector was the second worst performer losing 1.67 per cent to 3,487.72 as Hindustan Unilever, the largest household products maker, plunged 5.45 per cent to Rs 281.65, its steepest drop since July 2009 after its Q3 profit fell as higher input costs reduced operating margins.

With the general weakening trend, the heaviest weighted Reliance Industries dropped by Rs 12.50 to Rs 958.55 and second-heavy Infosys Technologies by Rs 24.10 to Rs 3,254.10.

A rise in stocks of Consumer Durables, Capital Goods and Power Sector, cushioned the market from a major fall.

The market will be closed on Wednesday, the Republic Day.