Sheeeeeeesh! Not a big deal. there are literally dozens of these supposed plaintiffs securities class action law firms that put out these notices on a daily basis claiming they are looking into every publicly traded company that has seen a significant drop in its stock price. These firms have literally made a cottage industry off of this, but the vast majority of the claimed investigations don't amount to anything. The link you posted is just one of many such notices on AXGN over the past several weeks and month since it dropped.
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