Dec. 16 (Bloomberg) -- Sony Corp., the world’s second- biggest consumer-electronics maker, fell to the lowest in a week in Tokyo trading after Credit Suisse Group AG cut its investment rating on the company, citing a loss of competitiveness.

Sony dropped 5.9 percent to close at 1,825 yen on the Tokyo Stock Exchange, the lowest since Dec. 8. The Nikkei 225 Stock Average lost 1.1 percent.

The Tokyo-based company needs “fundamental changes” to its operational structure, in addition to job cuts announced last week, to avoid lagging further behind rivals including Apple Inc. and Nintendo Co., said Credit Suisse, which reduced its rating on Sony to “underperform” from “neutral.”

Separately, Deutsche Bank AG cut its recommendation yesterday to “hold” from “buy,” and slashed its share-price estimate by 49 percent to 2,050 yen, because of Sony’s high level of operating costs.

“We believe fundamental changes to its business structure are necessary,” Koya Tabata, a Tokyo-based analyst at Credit Suisse, wrote in a report released after the close of trading yesterday. “Compared to its peers both at home and overseas, Sony has been slow to react to the current crisis.”

Tabata widened his forecast of Sony’s net loss for this fiscal year more than six fold to 150 billion yen ($1.66 billion), from a previously estimated 22.6 billion yen. Sony, the maker of Bravia liquid-crystal-display televisions, in October projected net income of 150 billion yen for the year ending March 31.

The analyst cut his full-year sales forecast to 8.1 trillion yen from a previously projected 8.9 trillion yen. That’s less than Sony’s prediction of 9 trillion yen.

The Credit Suisse analyst also cut his share-price estimate for Sony by 59 percent to 1,000 yen.

To contact the reporter on this story: Hiroshi Suzuki in Tokyo at Hsuzuki5@bloomberg.net

Last Updated: December 16, 2008 02:00 EST