DETROIT (AP) -- A health care trust for Chrysler retirees saw an 18 percent gain in the value of its assets thanks to the rising value of its stake in Chrysler.
In its annual report filed with the U.S. Department of Labor, the union-run trust said its net assets rose $1.58 billion to $10.29 billion between January and December of 2012. That was a bigger increase than those posted by trusts for General Motors Co. and Ford Motor Co. retirees.
That was largely because the value of its 41.5 percent stake in Chrysler rose by $900 million to $3.6 billion. An independent fiduciary calculates the value of the stake.
The trust paid $631 million in benefits to 61,214 people last year.
Chrysler Group's majority owner, Italian automaker Fiat SpA, wants to buy the trust's share of Chrysler, but says the stake is worth $1.75 billion.
The trust wants Chrysler to determine the value through a public offering of its stake. Chrysler filed the paperwork for an initial public offering last month, but the two sides could still reach an agreement about the value of the stake without an IPO.
Chrysler shares haven't been publicly traded since 1998, when the company merged with German automaker Daimler AG.
GM's trust said its net assets rose 5.8 percent to $29.9 billion, while Ford's trust said its net assets rose 5.4 percent to $15.9 billion.