U.S. inflation expected to climb again

The next round of inflation chatter will kick 0ff on Thursday, when the Consumer Price Index for January is released at 8:30 a.m. ET.

State of play: Economists think it will show prices in January were up 7.3% compared to last year. If they're right, it'll be the fastest price rise since early 1982.

Why it matters: Inflation is the single most important issue for investors to understand this year.

• If prices continue to arrive higher than economists — and the Federal Reserve — expect, then the central bank could raise rates fast. That's something hardly anyone has been expecting.
• It was just such a realization — that the Fed was going to lift rates soon — that pushed the market to one of the ugliest starts on record this year. The S&P 500 was down by nearly 10% at times in January.
• It's since clawed back a fair bit and is about 5% lower.

What we're watching: The two largest drivers of the surprisingly high inflation in recent months have been the costs of shelter — up 4% in 2021 — and used cars — up 37%(!). Any big moves in those categories could translate into a big swing in the official reading on prices.