I literally just came to HN after browsing slate.com for a bit, currently on their front page is an article about a railroad company that sent 86% of their lobbying money to Trump and GOP PACs this last election cycle. Half of this company's revenue is based in pesos and susceptible to dollar/peso fluctuations and its core business is related to moving goods back and forth between the US and Mexico. Trump took dead aim at free trade, and NAFTA in particular on the campaign trail. Self interest seems to play no part in who people (and companies, thank you Citizens United) choose to support.

http://www.slate.com/blogs/moneybox/2017/01/23/kansas_city_s...

Edit: expanded on why a for profit company being pro-Republican would be against its own self interest.