What happened

A Canadian transportation and logistics specialist disclosed an investment in U.S. trucking company ArcBest (ARCB -6.13%), and some investors are betting it is a precursor to a buyout. Shares of ArcBest jumped as much as 20% on Tuesday morning after the stake was disclosed.

So what

ArcBest specializes in truckload and less-than-truckload freight transport, logistics, and brokerage operations, with a focus on the central United States. The company is a solid performer, but not the sort of stock usually subject to major single-day price moves.

On Monday, TFI International (TFII -4.68%) disclosed it has built a 4% stake in ArcBest, leading to some speculation about a potential deal between the two companies. TFI is a Canadian transportation giant that has been looking to expand in the U.S., in 2021 acquiring the freight operation of United Parcel Service for $800 million.

On an earnings call, TFI CEO Alain Bedard explained the investment by saying, "We really like this company," but said there has been "no engagement whatsoever" about a potential merger. He also didn't rule out the possibility of future discussions, saying, "Down the road, we would like to talk because we have a lot of expenses that we could reduce if we worked together."

Now what

Reading between the lines, there is some logic behind investor enthusiasm. Bedard noted the similarities between ArcBest and TFI's TForce Freight trucking unit in terms of unionization and operating practices. He also mentioned that there is "a very large portfolio of real estate" within TForce that is currently underutilized.

Merger speculation is just that, speculation, and with the stock already in the fast lane, speculators should be careful now. Even if TFI is interested, there are no guarantees a deal will get done, and the stock could just as easily give up the gains.

ArcBest's current labor deals are up for renegotiation, making it a messy time for a suitor to even consider making an offer. But if the company is able to work out new agreements with the Teamsters and others by the June deadline, don't be surprised if TFI makes a call to ArcBest headquarters.