* Probe includes local and foreign companies
* Charges relate to price-fixing and information-sharing
* Auto sector Turkey's largest exporter, punishment unlikely
Turkey's Competition Board said on Wednesday it had opened an investigation into 19 of the country's largest auto companies, including foreign firms operating in Turkey, for alleged price-fixing since 2006.
Separately, Industry Minister Nihat Ergun said tax breaks on cars, introduced in March to boost sales in the automotive sector, will not be extended when they expire Wednesday evening.
The competition board said the firms, part of a strategic Turkish sector after a 2001 economic crisis, had been sharing targets, stock information and sales and pricing strategies.
Companies under investigation include Daihatsu Turkey, Dogus Otomotiv (DOAS.IS), General Motors Turkey, Honda Turkey, Hyundai Assan, Karsan Otomotiv (KARSN.IS) and Tofas (TOASO.IS), a joint venture between Italy's Fiat (FIA.MI) and Koc Holding (KCHOL.IS), the board said.
The decision has been made due to the sharing of targets, stock information and sales and pricing strategies since 2006, which is against laws protecting competition, the board said in a statement.
Turkey's proximity to Europe and lower labour costs have attracted foreign carmakers, transforming the automotive sector into the country's biggest exporter.
Other firms being probed are the Turkish units of Mercedes Benz, Nissan and Peugeot, as well as Toyota, which makes cars with Turkey's Sabanci Holding, the watchdog said.
Shares in Tofas were down 2.69 percent at 4.34 lira, while Dogus Otomotiv was down 3.77 percent at 5.10 lira at 0849 GMT in a broadly positive market.
Shares in Karsan had dropped 3.51 percent to 1.65 lira.
A source at Tofas who declined to be named told Reuters company officials had discussed the issue and Chief Executive Ali Pandir would make a statement later in the day.
Dogus Otomotiv and Karsan officials were not immediately available for comment.
I don't know how serious it is, but it is against all the auto companies in Turkey ... Considering that they are a major exporter and considering their place in the Turkish economy, I doubt there will be any punishment against the sector, said Cemal Demirtas, a senior analyst at Oyak Invest.
It is difficult to establish price fixing, he said, adding that car prices in Turkey are higher than European counterparts, mostly due to taxes.
The government cut special consumption taxes earlier in the year to boost domestic auto sales. Those cuts will expire Wednesday evening and will not be renewed, Ergun told reporters.
The government is considering a possible cash-for-clunkers programme that encourages automobile owners to exchange used vehicles for new automobiles, he said. (Additional reporting by Melis Senerdem in Istanbul and Hatice Aydogdu in Ankara, Editing by Will Waterman and David Cowell)