Aug 6 (Reuters) - Fortinet FTNT.O forecast third-quarter revenue below Wall Street estimates on Wednesday, as businesses cut back on spending amid widespread macroeconomic uncertainty stemming from global trade tensions, sending shares down 12% in extended trading.

U.S. President Donald Trump's ongoing global trade negotiations have led to an uncertain economic environment, prompting businesses to reassess significant investments, which has hurt demand for Fortinet's services.

The cybersecurity firm expects to generate revenue between $1.67 billion and $1.73 billion for the third quarter. The midpoint of this range is just shy of analysts' average estimate of $1.71 billion, according to data compiled by LSEG.

Fortinet offers integrated cybersecurity solutions, including firewalls, intrusion prevention systems and cloud-based threat protection, and competes with companies such as Palo Alto Networks, Cisco Systems and Check Point Software Technologies CHKP.O.

Consolidation in the industry is pressuring providers like Fortinet, as rivals such as Palo Alto Networks move to expand aggressively, which said last month it will buy Israeli peer CyberArk Software CYBG.F, for about $25 billion.

Fortinet raised its forecast for annual billings to a range of $7.33 billion to $7.48 billion, up from the prior range of $7.20 billion to $7.40 billion.

The company posted revenue of $1.63 billion for the second quarter ended June 30, in line with estimates.

Adjusted profit for the quarter stood at 64 cents per share, beating estimates of 59 cents per share.

(Reporting by Arsheeya Bajwa in Bengaluru; Editing by Tasim Zahid)

((ArsheeyaSingh.Bajwa@thomsonreuters.com; +91 8510015800;))