Nikola (NKLA 0.88%) -- yes, this company is still publicly traded -- slipped over 20% yet again this week, according to data from S&P Global Market Intelligence. The hydrogen-electric truck start-up keeps inflating its shares outstanding, insiders keep selling, and the company is nowhere near close to generating a profit. No wonder the stock is down over 99% from all-time highs.

The stock keeps falling, and it only has further to go, because this is not much of a real business. Here's why.

Insider selling and poor business results

Insiders keep selling at Nikola. This week, the COO, CFO, and president -- all important roles -- proposed to sell some of their stakes in the company.

Insider selling in a stock down 99% is never a good sign. Typically, you would want a management team confident in a business even if the stock is tanking, which would mean insider buys. This is the opposite.

It is clear why management is selling the stock: The business is very far from generating a profit. Last quarter, Nikola posted just $31 million in revenue and a net loss of $134 million. Over the last 12 months, it has burned $500 million in free cash flow on less than $50 million in sales.

Hydrogen fuel semi trucks are its main products and will apparently disrupt the transportation market. It has been saying this for years. The problem is, that this is not a technology that actually works.

Nikola has never generated much in revenue and keeps burning cash. It is no surprise then to see the stock down over 99% from all-time highs.

Take a good look at the shares outstanding 

Let's close on Nikola with a lesson in shares outstanding. If you are an outside shareholder in a stock, you want shares outstanding to go down through share buybacks. That way, you own more and more of the business each year. It is a red flag if a company's shares outstanding keep going up, as it shows it needs to sell more stock to other people in order to finance operations. Profitable companies do not need to do this.

Nikola's shares outstanding are up 300% in the last few years. This is a huge red flag and happened because the company is burning so much in free cash flow. It keeps running out of cash and then sells stock in order to stave off a bankruptcy filing. All this means this is not a stock you want to own for the long haul.