Supply and demand.
Demand: While I sit here typing on my keyboard, Tesla is deliverying more and more cars. These owners take delivery and could possibly love the car so much they buy the stock. This is a continuous and endless stream. Add to that the neighbor effect - the neighbors see the new car, wonder about it, search for it, are intrigued by it, can't afford it (or order one), and consider buying the stock. This is also a continuous stream as long as Tesla keeps deliverying cars (since there is no advertising present except for this word of mouth.) Over the long weekend, people get together and talk - likely about what they want to talk about and for many people this might include their new car (Tesla) and how their stock is giving such a great return. Convinced people in turn buy the car / stock come Tuesday. In the process, Multiple news outlets keep regurgitating the stories about Tesla paying back the loan, the kindergartenders fitting into the car, the Goldman Sachs visit of the factory, and various other news that keeps the brand in the consciousness of the retail/instituitional investors. Many are adding to their positions seeing the meteoric rise, etc. etc. etc.
Supply: While I sit here still typing away on my keyboard, the total number of shares doesn't change. We're done with the share offer so whatever you can buy comes from others who are willing to sell - at a profit.
Increaming demand with no increase in supply invariably only leads to..... the price of the stock increasing.
