Snap shares have tumbled since its March initial public offering. One Wall Street firm believes there will be no turnaround for the social media firm’s stock anytime soon.

SunTrust Robinson Humphrey on Tuesday initiated coverage for Snap shares with a sell rating, citing the competitive threat of its larger rivals copying its innovations.

Snap’s “challenges around bringing advertisers onto the platform at scale, and getting a sizable portion of their ad spend short term are likely to take time to overcome, causing the stock to underperform,” analyst Youssef Squali wrote in a note to clients. “We also note a massive lock-up expiration of shares in the last two weeks, intense competition from Instagram/Facebook for users and advertisers.”

Squali started his price target for Snap at $10, representing 21.5 percent downside from Tuesday’s close. Despite the call, Snap shares rose 1.7 percent in early trading Wednesday. The stock bounced off its all-time low set on Monday as some on Wall Street speculated the worst is over.

The analyst cited how Facebook added Snap-like features to many of its properties such as Instagram, Messenger, WhatsApp and Facebook site itself. He noted 200 million people already use Instagram Stories, which is now larger than Snapchat’s user base.

“Facebook/Instagram and YouTube are quick followers, constantly improving their value proposition as well, at materially greater scale,” he wrote.

Snap’s share price is down 57 percent from its high, reached days after the company went public on March 2. It is also down 25 percent from the $17 IPO price.

Its shares are down significantly from their high on weaker-than-expected second quarter earnings, big insider selling lockups, increasing competition from Facebook and big-name hedge funds dumping the stock.

Nearly 70 percent of Wall Street does not have buy ratings on Snap shares, according to FactSet. Such a mixed view after a large technology IPO is a rarity.

Snap did not immediately respond to a request for comment.

Disclosure: CNBC parent NBCUniversal is an investor in Snap.