DST Systems reported third-quarter net earnings of $70.6 million, or $1.43 a share, up 10.8% from $63.7 million, or 92 cents a share, in the third quarter of 2007.

The company attributed much of the quarter’s strength to the sale of 730,000 shares in State Street worth $25.4 million. DST acquired the stock when it sold one of its subsidiaries to State Street; the firm still holds 10.6 million shares.

The sale offset a $27.4 million decline in DST’s investment portfolio, which the company said it did not expect would be temporary.

However, the number of mutual fund client accounts that DST services fell by 3.8 million in the third quarter, and revenues themselves declined slightly to $564.3 million from $577.4 million a year earlier.