Sony shares tumbled below 1,000 yen for the first time since 1980 as the Tokyo stock market plunged early Monday following a dismal performance from Wall Street and amid global economic concerns. The entertainment and electronics giant dropped 2.3 percent to 990 yen shortly after the opening bell, before recovering to 1,001 yen as of 11:20 am (0220 GMT). Dealers said Sony last traded blow the psychologically important 1,000 yen level in August 1980 around a year after its landmark \"Walkman\" portable music player was released. Sony posted a record full-year loss of 456.66 billion yen ($5.8 billion) for the year to March 2012 as it struggles with losses in its television division. Japanese companies have blamed tough competition from rivals including South Korea\'s Samsung, falling prices, slow demand, the impact of severe flooding in Thailand last year, and the high yen for their travails. The stronger yen hits Japanese exporters by making their products more expensive overseas, while eroding the value of foreign-earned profits.