What happened 

Shares of Westinghouse Air Brake Technologies Corp. (NYSE: WAB) fell as much as 13.9% in trading Friday as investors headed for the exits before the weekend. As of 3:20 p.m. EDT, shares were still down 11.7% on the day. 

So what

There wasn't any major news today, but there was some notable news earlier this week. On Wednesday, the company priced an offering of $2.5 billion of senior notes, which closed Friday morning. It will be used to acquire GE's transportation business and the $2.9 billion of cash owed. 

Train moving through the mountains.

Image source: Getty Images.

Investors have known about this offering for a few days, but today is when it hit the stock. Traders might also be seeing more risk in the stock, now that it has more debt on the balance sheet. 

Now what

I wouldn't read too much into the move today. Sometimes stocks can swing wildly even on little news, and I wouldn't call the closing of senior notes a bigger news item than it should have been a few days ago. The value for shareholders will be added if GE Transportation makes money, and that's a long-term play on the future of rail transportation. 

Travis Hoium has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Westinghouse Air Brake Technologies. The Motley Fool has a disclosure policy.