What happened

Shares of electric-heavy-truck start-up Nikola (NKLA -1.48%) were trading higher on Thursday, after it confirmed that it is open to partnering with Korean auto giant Hyundai (HYMTF 0.09%) on hydrogen technology -- even though the two companies could become rivals. 

As of 3 p.m. EDT, Nikola's shares were up about 5.5% from Wednesday's closing price.

So what

In an interview published on Sunday by South Korean newspaper Chosun Ilbo, Nikola founder Trevor Milton said that he would like to cooperate with Hyundai on hydrogen fuel-cell technology. Such a deal, which might include technology-sharing or an agreement by Hyundai to manufacture fuel cells for Nikola, could be a boon for the truck start-up.

A red Nikola electric semi, shown hauling an Anheuser-Busch trailer.

Nikola's electric semis will be offered with both battery-electric and hydrogen fuel-cell drivetrains. Image source: Nikola Corporation.

In the interview, Milton said he believes that Hyundai has excellent fuel-cell technology, and that Nikola could become a $100 billion company with Hyundai as a partner. Milton said that Nikola has so far made two proposals to Hyundai, but both were rejected. 

On Wednesday, a Nikola spokesperson confirmed to Reuters that Milton "has immense respect for Hyundai" and views the company as a leader in hydrogen technology. She confirmed that Nikola is open to collaborating with Hyundai, but did not comment on whether Nikola had made proposals to Hyundai.

Now what

On the one hand, that's pretty thin stuff to spark a 5% rally. On the other, given the intense interest in electric-vehicle stocks at the moment, it's not too surprising that a report floating just the possibility of a deal with Hyundai gave Nikola's shares a boost.

In this and many other areas, Nikola has great plans and great ideas, but it needs time to show that it can execute. I'd file this report in that folder: A deal with Hyundai could be a significant catalyst for Nikola's stock, but I encourage auto investors to wait to see evidence that it's more than an interesting idea before rushing to buy.