Yet another government official faces potential criminal charges after clashing with President Donald Trump. This time, the head of the Federal Reserve Board is under federal investigation over testimony he gave to Congress. He and many observers see another example of Trump using the justice system to go after his opponents.

The Federal Reserve has several tools to manage the money supply and keep the economy running smoothly. Learn how the central bank sets monetary policy.

Economists have long preferred independent central banks because they can more easily take unpopular steps to fight inflation, such as raise interest rates, which makes borrowing to buy a home, car, or appliances more expensive.

The chair of the Federal Reserve oversees the U.S. banking system and helps steer monetary policy. The chair's salary is set by the U.S. Congress.

B added, repo/RRP volatility, deposit swings, and inflation risks amid politics. Read more macro analysis here.

The Secretary of the Treasury suspended production of the 1-cent coin, with the final penny pressed Nov. 12., after determining it was no longer needed—and becoming increasingly expensive to make. The cost to produce the penny has increased from 1.42 cents to 3.69 cents per penny, according to the United States Mint.

The Fed is a separate agency from the U.S. Treasury, but both are responsible for keeping the economy stable. Here's the difference between the two bodies.