S&P 500 index prolonged losses on Thursday, experiencing the worst week in 2012. US benchmark shed 0.06% or 0.88 points and closed at 1,398.08. Bed Bath & Beyond rallied 9.2% after the retail-chain operator reported a better than expected 4th quarter profit. First Solar made the biggest drop falling 16% after JPMorgan Chase & Co cut its share price estimate and claimed firm's profit margin will tumble further. Avon products added 3% as it rejected the bid from Coty.