I see double-digit stock gains in 2015: Tom Lee

2015, year of the sector: Tom Lee

Investors don't seem to be overly optimistic about stocks, and that's a "very bullish" sign, longtime market bull Tom Lee told CNBC on Monday.

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The Nasdaq Composite is aiming at 5,000, a level not seen since March 2000, when the index peaked at 5,135, before beginning a multiyear slide as the dot-com bubble burst.

The Dow Jones Industrial Average and the closed at record highs on Friday, after a third straight week of gains. (Check here for the latest on the markets.)

Lee said in "Squawk Box" interview he still thinks stocks will go higher in 2015. "I think double digits sounds right from here into the end of the year." He sees the S&P at 2,325 by year end, which would represent another 10 percent from Friday's close. So far in 2015, the S&P has gained just over 2 percent.

But the co-founder and head of research at Fundstrat Global Advisors said the real opportunity for investors this year will be picking the right sectors. "This is really the year where you see sectors pulling away. So I think whether it's tech or consumer, I think some of these groups are going to make bigger moves than that."

Acknowledging estimates for earnings growth this year have been coming down, he argued, "I do think you are going to see earnings rise through the year" as the benefits of the collapse in oil prices are realized.

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