(Closes shares in sixth paragraph.)

Aug. 23 (Bloomberg) -- A-Tec Industries AG, which filed for insolvency last year, asked potential buyer Penta Investments Ltd. to narrow its offer to just one of the Austrian engineering company’s units.

Penta, a Prague-based investment company, was approached last week by A-Tec Chief Executive Officer Mirko Kovats, who asked it to bid for only the minerals and metals division, said Jakub Korinek, Penta’s investment manager in charge of the bid.

“We’re currently assessing the proposal, however we consider this change surprising and confusing,” he said in a phone interview from Vienna today.

A-Tec, majority owned by Kovats, filed for insolvency on Oct. 20 last year after efforts by the Vienna-based company to refinance a bond failed. The insolvency is Austria’s third largest in postwar history.

“We stand behind our original offer that is in line with the insolvency rules,” Korinek said. He wouldn’t comment on whether a price for the unit was discussed. A-Tec declined to comment on a narrowing of bids.

A-Tec fell 3.4 percent in Vienna to 1.92 euros at the 5:30 p.m. close of trading in Vienna, erasing earlier gains of as much as 4.9 percent. Shares have declined 48 percent this year, valuing the company at 51 million euros ($74 million).

Penta, a Czech and Slovak private equity group, submitted a bid to buy and restructure all A-Tec assets in June. Other bidders for A-Tec include hedge fund Springwater Capital and Pakistani billionaire Alshair Fiyaz, Format magazine reported, without citing anyone. The company’s supervisory board is meeting tomorrow to discuss bids, according to Format.

Founded in 1994 as a stock brokerage, Penta moved into private-equity investments in 2000. It controls about 30 companies, including retail chain Zabka Polska SA and Aero Vodochody, a Czech aircraft producer. Penta has 2.7 billion euros ($3.63 billion) of total assets, according to its website.

--With assistance from Boris Groendahl and Zoe Schneeweiss in Vienna. Editors: James M. Gomez, Alan Crosby

To contact the reporter on this story: Lenka Ponikelska in Prague at lponikelska1@bloomberg.net.

To contact the editor responsible for this story: James M. Gomez at jagomez@bloomberg.net