Hedge-fund manager Ellington Management Group's Ellington Financial LLC subsidiary has filed to hold an initial public offering as the specialty-finance company looks to raise money to acquire new assets.

In its registration documents with the Securities and Exchange Commission, Ellington Financial put the planned IPO's size at $200 million.

Ellington Financial, which will list its common shares on the New York Stock Exchange with the symbol EFC, was formed with $250 million from its parent company in August 2007.

A spokesman for Ellington declined to comment, citing "quiet period" rules surrounding IPOs.

Ellington Financial invests in residential mortgage-backed securities, or RMBS, backed by subprime, "Alt-A" and other mortgage loans. It also invests in both mortgage-related and other types of derivatives.

In the IPO filing, Ellington Financial said it has delivered a positive total return on capital since its inception in August 2007. However, investors may be wary of the risks associated with the RMBS the company deals in as the real-estate market is still struggling amid tight credit markets and high inventories.

Ellington Management, the parent, is considered a pioneer among hedge funds that trade mortgage-backed securities. It was founded in 1994 by Michael Vranos, former head of mortgage-backed trading at Kidder Peabody. It ran into trouble in its funds last year, along with most managers of mortgage-focused funds. After barring withdrawals, Ellington split its main fund in two in order to slowly liquidate hard-to-sell assets, and laid off some employees.

Only three U.S. hedge fund managers have publicly traded shares: Och-Ziff Capital Management Group LLC (OZM), Blackstone Group LP (BX), and Fortress Investment Group (FIG).

For the quarter ended March 31, Ellington Financial's net investment income jumped 61% to $6.3 million from a year earlier, while its net realized gain on investments and hedging soared to $19.8 million from $1.5 million. It realized a loss on investments during the quarter amid stock-market volatility, but saw a big gain on its derivatives.

Ellington Financial, which had announced in April its IPO plans, said it would use the proceeds to acquire targeted assets within six months of the closing of the offering. Remaining proceeds would be used for general corporate purposes.

-By Joseph Checkler; Dow Jones Newswires; 212-416-2152; joseph.checkler@dowjones.com

-By Kerry Grace Benn, Dow Jones Newswires; 212-416-2353; kerry.benn@dowjones.com