BSE Sensex was down by more than 100 points on Friday, amid selling in heavyweights.Among the Sensex stocks, Bajaj Finance was down by more than 6 per cent. Bajaj Finserv was down more than 2 per cent.Among the gainers, Tech Mahindra was up more than 8 per cent. BSE Sensex was trading at 74,234 points, down 105 points.