Feb 14 (Reuters) - Citadel Securities, the market maker owned by Citadel's Ken Griffin, on Tuesday reported a 5.5% stake in cryptocurrency-focused lender Silvergate Capital Corp worth about $25 million, according to a regulatory filing.

Shares in Silvergate jumped after the disclosure, and were last up about 14%.

A representative for Silvergate did not immediately respond to a request for comment.

The filing was a result of the firm's market making operations as opposed to a directional investment in Silvergate, according to a person familiar with the matter.

On Monday, Soros Fund Management disclosed a bet against Silvergate in a regulatory filing, which showed a put options position against 100,000 shares of Silvergate as of Dec 31. Based on Silvergate's closing price of $17.40 at the end of 2022, the value of those shares would be about $1.74 million.

Put options give investors the right to sell shares at a certain price in the future.

Details on the strike price of the puts, their value and whether they are part of a broader trade were not available. A representative for Soros Fund Management did not immediately respond to a request for comment.

Silvergate has been seeking to ease investor concerns over its future, after reporting a $1 billion loss for the fourth quarter because crypto exchange FTX's bankruptcy shook confidence in the digital asset sector.

Federal prosecutors in Washington are probing Silvergate and its dealings with FTX and Alameda Research, a source familiar with the investigation has said.

U.S. custodian bank State Street Corp reported a 9.32% passive stake in Silvergate earlier this month. (Reporting by Hannah Lang in Washington; additional reporting by Saqib Ahmed; Editing by Leslie Adler and Jane Merriman)