Snapping a four-day rising streak, the BSE benchmark Sensex fell by over 40 points in early trade today as funds and retail investors booked profits at prevailing levels. The 30-share index, which gained over 547 points in the last four sessions, fell to around 17,390 with stocks of oil and gas, auto and banking sectors succumbing to profit-booking.Similarly, the wide-based National Stock Exchange index Nifty declined by nearly 12 points, to 5,267.