Wall Street's No. 1 small-cap strategist hasn't been this bullish in years, sees 12% gain in 2021

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Wall Street small-cap market guru Steven DeSanctis is giving his most bullish forecast for the group in over a decade.

The Jefferies analyst estimates that benchmark Russell 2000 will rise more than 12% to top the 2,050 level in 2021. Next year's call is Jefferies' most bullish for the index since 2003.

Jefferies expects small caps to outperform large caps by 6.4% next year, which would be the first time small caps do better than large caps since 2016.