The prospect of lower profits and higher spending next year sent shares of Charleston-based Blackbaud Inc. tumbling on Wednesday.

The Daniel Island-based software company's stock fell more than 16 percent from its $42 opening to close at $35.30. Nearly 695,000 shares changed hands, triple the 30-day average.

The sell-off followed Anthony Boor's first earnings call as interim president and chief executive officer. He assumed the top job on a temporary basis Sept. 1 to replace Marc Chardon.

Blackbaud is one of the region's largest technology businesses. Its specialized software products target nonprofit organizations that raise money from donors.

The company reported revenue of $128 million for the July-September period, up 4 percent from a year ago. Profits more than doubled to $9.4 million, driven largely by a $7.4 million drop in expenses.

"Each of our business units delivered a solid performance in the third quarter," said Boor, who also is chief financial officer.

The reaction in the stock market showed that investors were more fixed on the year ahead.

"We are early in our 2014 planning process, but we are anticipating that we will be balancing between investments for accelerated long-term revenue growth and continuing to stream on our cost structure," Boor said.

As a result, Blackbaud expects to "experience a moderate reduction" in its profit margins as it moves to beef up research and development and expand its sales force, he said.

Analyst Matt Kemper of Sidoti & Co. asked him whether the company was reacting to past under investments or new business opportunities. Boor said in his response "we're still well behind on R&D investments, headcount investments and sales and marketing heads."

"While we were underinvesting in certain areas, we may have overcut in a couple of others and then we've just had a difficult time hiring as quickly as we would have liked to," he said.

The extra spending is expected to begin before the end of 2013, prompting Blackbaud to lower its fourth quarter profit guidance as well.

"We anticipate these investments will position Blackbaud for further acceleration in our revenue growth in the coming years," Boor said." We're very mindful of the fact that we're spending shareholders' money to make these planned investments in '14, and we strongly believe that these investments will generate the most long-term value for our shareholders."

Blackbaud also announced a quarterly dividend of 12 cents a share. It'll be paid Dec. 13 to stockholders of record Nov. 27.