The capital market is dedicated to the sale and purchase of long-term debt and equity instruments. The term encompasses the entire stock and bond markets. Certainly, anyone can buy and sell a stock in a fraction of a second these days. However, the company issued the stock for the purpose of raising money for its long-term operations. Its value fluctuates but it has no expiration date unless the company itself ceases to operate.
In 2008, following the bankruptcy of Lehman Brothers, the venerable Reserve Primary Fund broke the buck: It held millions of Lehman's debt obligations, and panicked redemptions by its investors caused its NAV to fall to 97 cents per share. The pullout of money caused the Reserve Primary Fund to close and triggered mayhem throughout the money markets.
Looking closer we see that if you can meet the $3,000 minimum investment size, Vanguard’s VMMXX offers an appealing combination of relatively high returns with low expenses. If you don’t have a large amount of cash to invest, you should note that both FMPXX and FIDXX have $1MM investment minimums. If you have less than $1,000, SPRXX doesn’t meet the yield and expense ratio thresholds we laid out, but it doesn’t have an investment minimum.