MEMX, as the exchange is known, was founded by nine leaders in the financial services industry in 2019, among them Morgan Stanley, UBS and Fidelity Investments.

"Participants in today's equity markets deserve an innovative alternative that is aligned with their interests, which is why we are pleased to support the launch of this new trading platform," said Vlad Khandros, UBS's managing director and global head of market structure and liquidity strategy, in a 2019 press release.

The MEMX will start trading seven symbols upon launch including Google parent Alphabet, ExxonMobil and Blackberry LTD and then the following week will provide all National Market System symbols.

Stock exchanges, which act as a marketplace for buyers and sellers of securities, make money from a number of different fees: transaction fees on trades; listing fees for listing a company on the exchange and market data fees.

Investment banks and financial services firms have raised concerns about the impact of high fees charged by existing stock exchanges, particularly for their market-data feeds.

"We've been quite vocal about the rising cost of data," Jason Sippel, global head of equities and prime services at JPMorgan, told the Wall Street Journal. "Lowering data costs will benefit all of our clients."

MEMX is just one of the new stock exchanges launching this month. On September 17, the Long-Term Stock Exchange (LTSE), launched, followed by Miami International Holdings Inc which has a new equities exchange called MIAX Pearl that is set to launch on September 25.

"We created the Long-Term Stock Exchange because we really felt like today's public markets have become overly short-term focused and there's really a lot of short-term pressures and we wanted to counteract that," said Michelle Greene, president of LTSE, in a press release.

In 2019, the US had 13 stock exchanges, Reuters reported. But all of these exchanges, apart from one, were controlled by one of the three big players in the markets: Nasdaq Inc, CBOE Global Markets or Intercontinental Exchange Inc.

Despite the influx of new competition, in a request for comment from the Securities and Exchange Commission on MEMX in 2019, Nasdaq appeared to welcome the new exchange.

"As a general matter, Nasdaq strongly supports competition as it motivates us to improve ourselves by striving to become ever more nimble, disciplined, efficient and creative," said John Zecca, executive vice president and global chief and legal regulatory officer of Nasdaq, in a letter.