The year's biggest deal is far from certain (AET, CVS)

CVS Health's massive acquisition of Aetna could face heightened regulatory scrutiny amid the Trump administration's new regulatory regime.
Aetna's stock is trading about 10% below the per-share offer price, reflecting investor uncertainty that the deal will get approval.A year ago, CVS Health's $69 billion acquisition of Aetna would've probably skated past regulatory proceedings. But things have changed under the Trump administration, and investors don't look particularly confident that the meg