Artnet AG (ART) founder Hans Neuendorf and his son Chief Executive Officer Jacob Pabst fended off a hostile takeover bid for the art-market-data provider from Luxembourg- based Redline Capital Management SA.

In an annual general meeting yesterday that stretched until midnight, shareholders backed the management’s proposals, approving changes to the company statutes that strengthen Neuendorf’s position in defending Artnet from takeover bids, the company said in a statement sent by e-mail. The shares fell as much as 12 percent today, decreasing the company’s value to 24.4 million euros ($30 million).

“Redline’s attempt to take over a majority of Artnet has failed, at least for the time being,” the company said in the statement. “We do not need investors who are interested in raising their profile and profit instead of in art,” the statement quoted 74-year-old Neuendorf as saying.

Berlin-based Artnet operates a widely used database of auction prices, and offers analytic reports and a platform for online art auctions. Redline, which says it controls more than 10 percent of the company, had offered financing support to counter what it described as Artnet’s “chronic lack of capital.”

Russian Billionaire

Redline’s chairman is Russian billionaire Vladimir Evtushenkov, who controls Moscow-based investment company Sistema JSFC. (AFKS) Sistema owns majority shares in OAO Mobile TeleSystems, Russia’s largest mobile-phone operator, and the oil producer and refiner OAO Bashneft. (BANE) Sistema also controls about 49 percent of Russian oil producer OAO Russneft.

Galerie Neuendorf AG owns 26.5 percent of Artnet shares, according to data compiled by Bloomberg. Shareholders yesterday approved limits to their rights, meaning in the future, changes to the company statutes will require the backing of stock-owners representing three-quarters of the company’s capital.

Redline is obliged by law to make a detailed takeover offer this month after announcing its intention to do so, Hans Obermeier, a spokesman for the company based in Frankfurt, said in a telephone interview. Shareholders last night said they plan to initiate legal proceedings against Artnet’s management and Redline is considering similar steps, Obermeier said.

“The company could now face a legal blockade,” Obermeier said. Shareholders accused Neuendorf and one of his employees of “acting in concert,” pushing their share of the votes above 30 percent, he said. Under German law, that would require them to make a takeover offer to other shareholders, he said. Pabst dismissed the accusations at yesterday’s meeting.

Pabst, 40, replaced his father as CEO on July 1. He said Artnet is seeking to increase sales and profits in 2013. Artnet said its online auction business is growing 23 percent annually, with as many as 70 sales a week.