Twitter’s ad business was up in Q2 – but it still took heat on the stock market for a slight decrease in monthly active users against the previous quarter.

The results, announced July 26, showed a 24% increase in revenue year-over-year (up to $711 million). Advertising revenue increased by 23% and came to $601 million. Ad engagements also increased by 81%. Daily active users were up (although Twitter does not disclose its total daily active users) and monthly active users were up year-over-year (335 million, versus 326 million from Q2 2017).

However, its monthly active userbase declined slightly from the previous quarter (approximately three million lost).

In the earnings call, Twitter attributed the loss to several factors, mainly not moving to paid SMS carrier relationships in some markets where users have better access to Twitter, as well as some impact from GDPR and several platform changes mainly focused around identifying and reducing spam, such as acquiring Smyte to detect and deactivate spam accounts.

At market close on Thursday just prior to the company’s announcement, Twitter’s stock sat at $42.94 USD per share. On Friday morning, it decreased to $37.32 per share – an 18% drop. While the decrease is significant for Twitter in the context of recent weeks, its stock has only been consistently above that price per share since June 4. Twitter’s stock remains more than double what it was last July.

Ned Segal, CFO at Twitter, clarified later that many of the fake accounts it had deactivated in a high-profile purge last month are not typically included in Twitter’s reports as they have not been active in the 30-day window to be considered a monthly active user. However, the company added in its shareholder letter that monthly active user count could continue to decline next quarter due to the ongoing changes.