By Josh Beckerman
Arrowhead Pharmaceuticals shares rose 7% to $20.28 as the company was selected to join the S&P SmallCap 600, effective Friday.
Meanwhile, S&P Dow Jones Indices said is removing construction company Orion Group Holdings from the SmallCap 600, as it "has a market capitalization that is no longer representative of the small-cap market space."
Orion shares fell 4% to $2.23 after-hours.
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