Twitter Inc (NYSE:TWTR) shares slipped on Monday after a downgrade from analysts at Oppenheimer. The stock soared by more than 20% on Friday after media reports that Salesforce or Alphabet is close to buying it. Despite the pullback on Monday, investors who had a position in Twitter before the takeover rumor was renewed on Friday are still in the green—at least as of this writing anyway.

Oppenheimer’s downgrade follows a downgrade from RBC last week, although that was before the renewal of the buyout rumor.

Twitter Inc (TWTR) Downgraded After Buyout Rumor Renewed

Twitter (TWTR): “the sixth best social media platform”

In a report dated September 26, Oppenheimer analyst Jason Helfstein downgraded Twitter Inc (TWTR) from Perform to Underperform and set his 12- to 18-month price target at $17 per share. He called the micro-blogging platform “the sixth best social media platform” and stated that it isn’t worth 20 times cash flow.

He noted that user growth continues to slow and that the growth of the company’s mobile app unique visitors greatly lags that of Snapchat and Pinterest. He reported a 10% increase in unique visitors in August, compared to 32% for Pinterest and 77% for Snapchat. He believes Twitter’s user interface remains difficult for new users to learn, which makes them unlikely to join. Also issues regarding the safety of the platform’s users are weighing on user growth, he believes.

Helfstein warned that engagement is also plunging, noting that total minutes per unique visitor declined 9% year over year last month. He added that this is also a long-term trend because in January, users were spending 153 minutes per month on Twitter, but that metric has now dropped to 143 minutes. In contrast, Snapchat users spent 266 minutes per month on it.

The analyst also warned that competitors are investing more in advertising technology and thus threaten to keep taking bigger and bigger bites out of Twitter. Additionally, the platform didn’t see a boost from the Olympics, which he noted is discouraging because Twitter would appear to be well-positioned for live events such as this. He was also disappointed with the NFL “experiment.”

Wall Street skeptical about rumor

Even though investors pushed Twitter Inc (TWTR) shares high on Friday after CNBC’s report that Salesforce was close to a buyout deal, analysts don’t seem to believe that the rumor is likely. Indeed, this isn’t the first time rumors of a buyout have surfaced and probably won’t be the last. Just this year alone, we heard similar stories in February and May. Stifel analyst Scott Devitt, who has a Sell rating and $9 price target on the stock, said on Friday that a deal is possible but unlikely. He said Alphabet could make sense as a suitor, but only “at a certain price.”

The reason is because Twitter Inc (TWTR) might make Google’s core platform more competitive with Facebook in social or real-time news and also possibly strengthen its position in streaming video. He feels it would also be good for Twitter because he believes Alphabet could more effectively monetize its ad inventory. However, he feels the valuation is too rich as if Alphabet does make an offer, it could mean it is a defensive move.

Costs higher than benefits in a Twitter buyout

Nomura analyst Frederick Grieb also sees an acquisition of Twitter Inc (TWTR) as possible but unlikely. He feels it could make strategic sense for Salesforce to buy the platform because it could integrate its own sales and marketing products with Twitter’s platform. He added that Salesforce was known to be interested in LinkedIn as well, which does indicate interest in social media.

However, he also believes buying Twitter would be both costly and risky for Salesforce, with the costs possibly outweighing the benefits. After the company’s shares surged on Friday, it was trading at an enterprise value of around $14 billion, which he noted would place it at about 20% of the combined enterprise value of both it and Salesforce combined.

He continues to rate Salesforce as a buy despite the possible talks about buying Twitter Inc (TWTR), and he hopes that the company would halt the talks (if any are taking place) after it sees how unhappy investors were with just the thought that it might buy Twitter.

Analysts from multiple firms expressed skepticism that a deal will happen and warned any potential suitors that it’s not a good idea. Twitter Inc (TWTR) shares slipped by nearly 3% to as low as $21.65 during morning trading on Monday.