Another Wall Street firm is getting less bullish on Snap.

Jefferies on Sunday lowered its rating for Snap shares to hold from buy, citing the company’s full valuation.

“We continue to have optimism around Snap’s platform, but fundamental execution needs to be shown before we can be more positive on the name,” analyst Brent Thill wrote in a note to clients. “We’ve also spent some time with the updated Snapchat app and see the positives, but also some negatives behind the redesign which could lead to some turbulence in usage and adoption when rolled out.”

Thill reiterated his $15 price target for Snap shares representing 3.5 percent upside to Friday’s close.

The analyst noted the company is trading at 11 times his 2018 sales estimate, which he believes is “fully valued.”

Snap shares are on a roller coaster ride since its IPO last March with its shares are down 16 percent in the past six months through Friday.

Cowen also reduced its rating for the company Thursday to underperform from market perform after it found ad buyers ranked Snap lowest relative to other social media companies.

Snap did not immediately respond to a request for comment.

The company’s shares are down 1.4 percent during Monday’s premarket session.

— CNBC’s Michael Bloom contributed to this story.

Disclosure: CNBC parent NBCUniversal is an investor in Snap.