Tesaro's low down payment

Investors rewarded Tesaro Inc. (NASDAQ:TSRO) with a $301.4 million gain in market cap after the company put just $17 million down for rights to cancer antibodies from AnaptysBio Inc.

Tesaro rose $8.38 (27%) to $38.86 on Thursday after acquiring exclusive, worldwide rights to AnaptysBio's monospecific antibodies and dual reactive antibodies targeting three immune checkpoint receptors. The specialty pharma gave back some gains but finished the week up $6.60 (22%) to $36.76, for a market cap gain of $237.4 million to close at $1.3 billion...