SCHAUMBURG, Ill. - Motorola Inc., the world's second-largest maker of mobile telephones, will reduce stockholders' equity by about $500 million this quarter to account for a decline in the value of pension-plan assets.

The company will determine the exact amount, the difference between the value of the assets and the amount Motorola must pay beneficiaries, on Dec. 31, Motorola said in a filing with the Securities and Exchange Commission. The action won't affect earnings, pension expenses or Motorola's cash-contribution requirements, the company said.

Some of the biggest U.S. companies are taking similar or larger charges this year to account for billions of dollars of pension-plan losses caused by stock market declines. Gains in pension assets boosted earnings as markets rose in the 1990s. Motorola's stockholders' equity totaled $11.3 billion as of Sept. 28, the company said in the filing.

Crain's Chicago Business newspaper reported the news in this week's issue. Motorola spokesman Scott Wyman declined to elaborate on the filing.

Motorola expects to contribute $150 million to $200 million in cash to the pension plan next year, the filing said. The company said it doesn't have to contribute anything in 2002. Motorola estimates it will have U.S. pension expenses of $85 million this year and $125 million in 2003, compared with $129 million last year.

As of Dec. 31, 2001, Motorola was obligated to pay $3.29 billion of regular pension benefits with assets valued at $2.96 billion for a $336 million shortfall, according to the company's proxy statement filed in March. Last year, Motorola paid $181 million in pension benefits, the filing said.

Motorola shares rose 46 cents to $11.70 on the New York Stock Exchange yesterday.