What happened

Shares of electric big-rig start-up Nikola (NKLA -5.51%) were down on Wednesday, as investors continued to digest a reality-check note from a Wall Street analyst earlier in the week.

As of 1:45 p.m. EDT, Nikola's shares were down about 4.9% from Tuesday's closing price. 

So what

Nikola's stock has had a torrid run since it went public via a reverse merger with VectoIQ Acquisition in early June. 

NKLA Chart

NKLA data by YCharts.

But that run hit a speed bump on Monday, when a note from a J.P. Morgan analyst gave excited investors some food for thought.

In that Monday note, J.P. Morgan analyst Paul Coster initiated coverage of Nikola with a neutral rating and a price target of $45. (For context, Nikola's shares closed at $65.90 last Friday.) Coster said that while Nikola is "poised to disrupt" the transportation industry with its deployment of hydrogen refueling infrastructure and upcoming fuel-cell-powered electric tractor-trailers, risks remain high given that the company currently has no revenue.

A silver Nikola Badger, a sleek electric pickup truck.

Nikola plans to reveal its Badger pickup on June 29. Will that be a catalyst for the stock? Image source: Nikola Corporation.

Now what

Long story short: While Coster believes that Nikola's business model "could be compelling," he feels the stock is fully valued. He feels that auto investors should wait to see either a pullback in price, incremental positive developments, or both before getting more bullish on the shares. 

I think that take, in addition to pressure from today's broad-based market sell-off on renewed COVID-19 concerns, explains why the stock's run-up has stalled for the moment.