Facebook has warned investors that investments in new products such as WhatsApp and Oculus Rift are likely to have a short-term impact on profitability, causing a 10% slump in its market value.

The social network yesterday (28 October) revealed third quarter global revenues of $3.2bn, with profits reaching $806m, up 90% year-on-year.

The growth was driven by a 64% increase in advertising revenue, reaching $2.96bn. Facebook continued to rapidly grow its mobile ad revenues: two-thirds of all ad revenues are from mobile, up from 49% in the same period in 2013.

Facebook also revealed that it now has 1.35 billion active monthly users, up 14% year-on-year.

“This has been a good quarter with strong results,” said Facebook founder and CEO Mark Zuckerberg. “We continue to focus on serving our community well and continue to invest in connecting the world over the next decade.”

However, in a subsequent call with analysts, chief financial officer Dave Wehner warned investors the company is likely to see a 55% to 75% increase in expenses during 2015, as Facebook turns its attention to recent acquisitions such as messaging service WhatsApp and virtual reality technology Oculus Rift.

Investors responded with disappointment, with shares in Facebook falling by almost 10% in after-hours trading.