Interactive Intelligence Group Inc. shares fell 25 percent in trading Tuesday morning, erasing more than $150 million in market value for the Indianapolis-based software maker.

The tumble followed a third-quarter earnings report that disappointed investors. Earnings at Interactive Intelligence fell 6 percent from the same quarter of 2010, well below analyst expectations, despite a 25-percent increase in revenue, the company announced late Monday.

Shares fell by more than $8, to $25.19 each, on Tuesday, flirting with a 52-week low.

Company executives said on a conference call with analysts Monday that some clients put orders on hold as the economic outlook darkened in recent weeks.  

“I think things got a bit scary for a while from an economic perspective, and we’re working on pretty big contracts here,” said Paul Weber, the company’s vice president of sales for North America. “It’s certainly nothing from a competitive perspective—we’ve never been positioned better than we are right now.”

Profit for the quarter ended Sept. 30 was $3.3 million, or 16 cents a share, compared to $3.5 million, or 19 cents per share, a year ago.

Revenue rose from $41.8 million to $52.1 million. But operating expenses jumped 29.5 percent, to $30.1 million, as the company experienced higher-than-expected growth in its cloud-based product line.

Orders for the company’s cloud-based software, which is accessed via the Internet rather than hosted at the customer’s premises, more than doubled in the third quarter, to 31 percent of total orders.

Cloud “is now the fastest growing part of our business,’’ company co-founder and CEO Donald Brown told analysts during the conference call.

Company executives played down quarterly earnings that came in well below analysts’ consensus prediction of 31 cents a share, saying Interactive sees its growth in cloud computing as a way to pass larger, traditional competitors amid the market shift.

Total company orders rose 14 percent, including 54 new customers.

Interactive Intelligence also recorded accounting adjustments related to three previous acquisitions, as well as expenses for stock options of $1.4 million, or 7 cents a share.

On the upside, the company scored the largest deal in its history, a $10 million cloud contract order.