Hungary's central bank (MNB) said Tuesday that it has bought back a majority stake in the country's stock exchange in an effort to boost weak trading volumes after years of sharp decline. The MNB bought a stake of 68.8 percent from two Austrian firms, CESEEG and OeKG, for 13.2 billion forints (42.5 million euros, $45.1 million), raising its overall holding to 75.8 percent. Trading volumes tumbled in 2014 to $6 billion from $34 billion seven years earlier, after the Hungarian government raised corporate taxes and seized pension-fund assets to prop up state finances.