JPMorgan analyst Paul Coster downgraded Vivint Smart Home (VVNT) to Underweight from Neutral with an unchanged price target of $15. The stock closed Tuesday up $2.70 to $25.65.

The analyst cites valuation for the downgrade with the shares up 149% year-to-date. The stock is currently "mispriced," Coster tells investors in a research note.

The analyst believes limited liquidity and thin analyst coverage may account for much of the stock's "erratic movement."