New investors fuel Bull Market

“Thirty years ago, commissions for stock trading were very high, the 10-year Treasury yield was at 6%, and exchange-traded funds (ETFs) were mostly a footnote in the investment landscape. In 1975, the Securities and Exchange Commission (SEC) had relaxed commission rates for equity trades, which ushered in an era of discount commission brokers such as Charles Schwab and Ameritrade.

Less expensive trading for investors, especially in retail, coincided with the start of the 1980 bull market. The combination of low-cost trading and a strong stock market helped fuel an initial public offering (IPO) surge. Unfortunately, this timeframe turned out to be the peak in the number of public companies in the U.S.”

Technology and other advancements including Global population growth (1994 5,675,551,255 - 2024 8.2 Billion) are fuel for an every increasing amount of investors in the public markets.

The stock market operates on the principle of supply and demand. When more people want to buy a stock than sell it, the price typically rises. 

https://www.bluetrust.com/blogs/why-has-the-number-of-public-companies-declined/