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Gary Shilling is predicting a recession and a steeep stock plunge by year's end.

The top economist said a downturn was almost inevitable, as consumer spending is likely to decline.

He sees the S&P 500 dropping as much as 30% as stocks get punished for inflated valuations.

Gary Shilling thinks there's almost nothing that can stop a US recession this year.

The legendary economist and Merrill Lynch alum laid out a grim outlook for markets and the economy in an interview with Business Insider this week. In his view, it's almost inevitable that the US will tip into a recession this year, given ongoing vulnerabilities in multiple areas of the economy.

He's also eyeing a big correction for stocks as valuations reach dizzying levels.…