The prospects for Tesla (NASDAQ:TSLA) stock turned positive over the last week. The stock has spent most of September rebounding from earlier lows. Now, the company has taken the unique step of having volunteers spread the word about discounts on cars and charging credits to raise revenues for Tesla stock.

However, the market cap of TSLA still exceeds that of GM (NYSE:GM), even though GM produced 96 times as many cars in 2017. While Tesla’s vision inspires a much higher valuation, it carries such a premium that it becomes difficult to measure whether the increases in the TSLA stock price will continue.

Tesla Stock Rebounded From Early September Lows

The company has taken the unusual step of calling on volunteers to promote the brand. They’ve also offered discounts on the Model S and charging credits to entice buyers.

It remains unclear whether this will further bolster Tesla stock. The negative sentiment that has plagued TSLA eased up slightly over the few weeks. After hitting a five-month low on Sept. 7, the stock has shot up. The stock has risen by about 23% from the intra-day low on that day. Now that the stock has moved north of $310 per share, observers wonder what it will do next.

Tesla Stock Trades on a Vision Premium

As most know, Tesla does not advertise. They rely on word-of-mouth. Now, the company wants to exert more direct influence on that word-of-mouth. This will likely serve Tesla well. For all of its problems, the Tesla brand has inspired an army of passionate followers comparable to that of Apple (NASDAQ:AAPL). Many envision a future where the internal combustion engine that defines GM, Ford (NYSE:F) and other traditional automakers goes away.

For those who buy Tesla stock, I see this as a “vision premium.” For better or worse, stock investors show a willingness to pay an outrageous premium for visionary leadership. This becomes even truer when that vision translates into high double-digit and triple-digit growth. GM stock enjoyed such a premium in the 1920s before losing more than 90% of its value during the Great Depression. Today, it appears in the stock prices of Amazon (NASDAQ:AMZN) and Netflix (NASDAQ:NFLX), as well as TSLA.

I believe the recent increase in TSLA stock shows the vision premium remains alive and well in the company. I have urged people to sell TSLA in past stories due to the high valuation inspired by the premium. So far, my negative vision has not come to pass. Missed production targets and outrageous antics by CEO Elon Musk has not permanently dampened the vision.

How Does One Measure the Vision Premium?

But here’s the thing with the vision premium — it remains difficult to measure. Amazon and Netflix earn a profit, so we can find limited latitude by which we can make a case for their stock prices. With Tesla stock, that becomes more difficult since it does not yet enjoy positive earnings.

It would not surprise me if these volunteers succeeded in boosting the revenue on TSLA for a time. If that translates into a higher Tesla stock price, that would merely reinforce the vision premium by which the equity thrives.

However, all vision premiums trade on psychology. Psychology remains hard to quantify for people in the psychology profession, let alone a financial journalist. We do not see Warren Buffett investing in Tesla stock, probably because he does not understand it. I do not understand it either. For that reason, I urge extreme caution, if not outright avoidance.

The Bottom Line on Tesla Stock

Tesla stock has risen over the last couple weeks, showing that the vision premium on Tesla stock remains alive and well. TSLA has recovered from the negative sentiment in August as Elon Musk’s behavior and word of turmoil inside Tesla inspired stock selling.

Today, TSLA stock again moves higher, and it has leveraged volunteer efforts and discounts to boost sales.

Still, all of these actions show the difficulty of measuring the vision premium on TSLA. We do not yet know how the latest efforts will affect Tesla stock. Also, like the GM of long ago, it will eventually lose the vision premium. We have no way of knowing whether that begins to happen tomorrow or years from now. Due to the difficulty of understanding the nature and level of Tesla’s vision premium, I urge investors to stay away.

As of this writing, Will Healy did not hold a position in any of the aforementioned stocks. You can follow Will on Twitter at @HealyWriting.