FANG stocks have run up this year and one strategist is seeing signs of the 2000 tech bubble.

Andy Kapyrin, director of Research at RegentAtlantic, said that Facebook (FB - Get Report) and Alphabet (GOOGL - Get Report) have strong advertising businesses, but if that momentum pulls back, the stocks could burst.

He points to negative publicity around Facebook with its Russia ads and the recent move by Procter & Gamble (PG - Get Report) to pull back spending on digital platforms. 

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