what is the name for a single company dominating an entire market
Market structure 3. Monopoly, where there is only one provider of a product or service.
Stock split For example, a company which has 100 issued shares priced at $50 per share, has a market capitalization of $5000 = 100 × $50. If the company splits its stock 2-for-1, there are now 200 shares of stock and each shareholder holds twice as many shares. The price of each share is adjusted to $25 = $5000 / 200. The market capitalization is 200 × $25 = $5000, the same as before the split.