Finance Minister P Chidambaram today advised retail investors in the stock market to exercise caution as the benchmark index nears the 18,000-point level, while welcoming the interest shown by foreign institutional investors."I do not think retail investors are entering the market at this level. I would advise them caution," he told reporters here.There is apparently lot of interest from foreign institutional investors, the Finance Minister said, adding: "Why should we not welcome it."The Sensex went up to 17,953 points in intra-day trading today, but came down from that level. At 1430 hrs, the index was ruling at 17,609 points, up 280 points over the previous day's close.With US Federal Reserve cutting interest rates amid concerns over slowdown in the world's largest economy, the FIIs are finding Indian stock markets quite attractive. Their net investments in local bourses stood at Rs 19,625 crore in September.He also said in case RBI approaches the government, it would review ceiling on Market Stabilisation Scheme Bonds, a mechanism to suck out liquidity which flows into the market because of the RBI intervention in the forex market.MSS Bonds' ceiling is Rs 1,50,000 crore per annum. Out of this, government has sucked out liquidity of Rs 1,42,000 crore so far this year.