A rally of more than 50% in shares Onyx Pharmaceuticals (NasdaqGS: ONXX) on Monday boosted biotech ETFs, the best-performing sector in early trading.
Onyx shares soared after the company spurned a takeover bid from Amgen (NasdaqGS: AMGN).
The company said the $120-a-share cash offer “significantly undervalued Onyx and its prospects.” However, Onyx has authorized its financial advisor to contact potential acquirers.
Onyx is a top-10 holding in Market Vectors Biotech ETF (NYSEArca: BBH) at 4.5% of the portfolio.
BBH was the largest gainer among unleveraged ETFs on Monday morning with a gain of more than 6%. Biotech has been a leading sector recently. BBH was up 28% year to date through the end of June to more than double the return of the S&P 500. [Biotech ETF Rallies as Cash Tumbles In]