There is typically a single dedicated/sponsoring market maker, but there are many numerous market makers on each individual stock.
NXTTF has over a dozen market makers participating in its market.
Market makers provide liquidity, and brokerages route their orders through a market maker, who conducts the trade on their behalf.
No, you can't become a market maker.
You would need millions of dollars and vast trading experience, for starters.
News 
Market Data 
Discover 
AI
