BTIG analysts halved their estimates for Snap’s 2020 revenue and apologized this week for not telling clients to sell Snap shares sooner.

“With the stock down 28 [percent] in the past six months since our initiation at Neutral, we were wrong to not have a SELL rating,” the BTIG analysts wrote. “[G]iven a complete lack of comfort with our updated forecasts shown below, we find it hard to be excited by the stock at current levels.”

Yet, the analysts still have not lowered their rating to “sell.” BTIG maintained a neutral rating on shares of Snap, the parent company of the social app Snapchat.

Here’s the logic behind the confusing call: BTIG is impressed with Snap’s U.S. growth in daily active users and engagement, in spite of competition from Instagram.

But the company’s ability to make money off each user is falling way short of BTIG’s forecast. At the beginning of the year, BTIG said it was confident that 2017 revenue would surpass $1 billion — but now it expects $859 million for the year. Given the slower growth rate on monetization, BTIG now expects Snap’s 2020 revenue of $4.1 billion, compared to its original forecast of $7.9 billion.

So why not sell the stock? Snap is one of the few investments in digital advertising, besides dominant players Facebook and Google, BTIG said.

“In that light, we remain intrigued by the potential of Snapchat and its ‘sticky’ user base making it difficult for us to see the stock as a compelling short at these levels,” the analysts wrote.

Snap reports Q3 earnings on November 7.

Snap was not immediately available to comment on the report.