Federal Reserve Board Chairman Jerome Powell (Image: EPA/Jim Lo Scalzo)

While the US Federal Reserve's 0.75 percentage point rate hike overnight is huge by historical standards, it comes after a period of preparation by the Fed and its chair, Jerome Powell.

The Fed sent tremors through US and global markets on Monday when it briefed The Wall Street Journal that a bigger increase of 0.75 percentage points would be "considered" at this week’s meeting. But the briefing successfully conditioned markets about what to expect -- and overnight, this week's equity market sell-off abated.

“Clearly, today’s 75 basis point increase is an unusually large one, and I do not expect moves of this size to be common,” Powell said about the decision, before saying he expected the July meeting to also see an increase of 50 or 75 basis points. He said decisions will be made “meeting by meeting” and the Fed will “continue to communicate our intentions as clearly as we can.”