The Nasdaq fell 2.46% as major tech stocks Apple, Microsoft and Amazon all declined more than 2%, while the S&P 500 closed down 0.77%. The Dow Jones Industrial Average ended the day up 27.37 points or 0.087%.
Entering the final week of February, both the Dow and the S&P 500 have risen about 5%, while the Nasdaq has climbed 4.5% on the month.
The 10-year Treasury yield also rose to 1.36% Monday, while the 30-year-yield hit a one-year high of 2.2%.
The price of bitcoin declined to $54,481.60 after Musk said the price of both it and ethereum, "seem high" in a response to a tweet from Peter Schiff, chief market strategist for the brokerage firm Euro Pacific Capital, about the cryptocurrency's value compared to gold-backed currency.
"An email saying you have gold is not the same as having gold. You might as well have crypto," Musk wrote. Money is just data that allows us to avoid the inconvenience of barter. That data, like all data, is subject to latency and error. The system will evolve to that which minimizes both."
Earlier this month, Tesla announced it had invested $1.5 billion in bitcoin and would soon accept the cryptocurrency as payment for some of its products.
Also Monday, Yellen described bitcoin as highly speculative and "inefficient" adding that it is often used for illegal transactions.
"I don't think that bitcoin is widely used as a transaction mechanism," Yellen said during The New York Time's DealBook DC Policy Project. "It's an extremely inefficient way of conducting transactions and the amount of energy that's consumed in processing those transactions is staggering."