I'm not a fan of Gianforte or anything, but this is a story with an alarming headline, with pretty pedestrian details. LafargeHolcim is a fairly major player in manufacturing globally, and Gianforte owned under USD50,000 (which, to an individual of Gianforte's wealth is a pittance) in shares in his and his wife's IRA.
In fact, I used to own shares in Dodge and Cox's International Fund, which holds a significant stake in LafargeHolcim, so Gianforte's holdings could theoretically also be through a fund.
Unsurprisingly, the details at the Huffpo's "report" are sparse, so I can't be sure, not that one should expect better from such a trash-tier site.
And yes, it was also stupid when R's did this "six degrees of Isis" to Hillary.