Ackman bought up 9.7% of Allergan's shares in February, reportedly in concert with Valeant, which announced its takeover bid in April. The tag-team approach was unusual, but legal experts told the Journal that the alliance doesn't appear to run afoul of SEC regulations. The article also notes that the early-stage probe into Ackman's and Valeant's joint tender offer (paywall) may not lead to any penalty by the financial regulator. Here's what a spokesperson for Ackman's hedge fund Pershing Square Capital told the Journal: "There is nothing illegal, unethical or improper in taking a toehold position before a merger is proposed, even if it is not wanted by the target's management. We welcome the SEC's review of the facts. Allergen filed a lawsuit against Ackman, Pershing Square, and Valeant on Aug. 1, alleging insider trading violations and a failure to disclose legally required information.