Federal Reserve Chairwoman Janet Yellen and her husband owned at least $4.6 million in assets last year, according to documents released Thursday by the U.S. Office of Government Ethics.

Fed officials' asset holdings are disclosed in ranges, so their total wealth can only be estimated. In 2013, Ms. Yellen and her husband, Nobel-winning economist and University of California, Berkeley professor George Akerlof, held assets worth $5.3 million to $14.1 million. The year before, their holdings were worth $4.8 million to $13.2 million.

Ms. Yellen has made unemployment a key focus of Fed policy, saying the central bank will keep its benchmark short-term interest rate near zero until officials see solid improvement in the labor market. With the unemployment rate falling quickly, to 6.2% in July, policy makers are increasingly debating when to start raising rates. Most Fed officials have indicated they expect to make their first rate increase sometime next year.

Many of Ms. Yellen and Mr. Akerlof's investments are in University of California-linked retirement plans. But they also hold interests in private companies, including Raytheon Co., Pfizer Inc. and Home Depot Inc. Their shares of each company were worth $1,001 to $15,000, the documents showed.

Ms. Yellen held on to her stamp collection, which is worth between $15,001 and $50,000.

Write to Pedro Nicolaci da Costa at pedro.dacosta@wsj.com

Corrections & Amplifications

This item was corrected at 6:44 p.m. ET because the original version misstated the value of assets owned by Federal Reserve Chairwoman Janet Yellen and her husband in the first and second paragraphs. The range of their holdings was $5.3 million to $14.1 million, not $4.6 million to $11.6 million.

The value of Ms. Yellen's stamp collection was also misstated in the last paragraph. It is worth between $15,001 and $50,000, not $50,001 and $100,000.

"Yellen Still a Multimillionaire, Records Show," published at 4:11 p.m. EDT, misstated the value of assets owned by Federal Reserve Chairwoman Janet Yellen and her husband in the first and second paragraphs. The couple owned at least $5.3 million in assets last year, not $4.6 million. The range of their holdings was $5.3 million to $14.1 million, not $4.6 million to $11.6 million.

The value of Ms. Yellen's stamp collection was also misstated in the last paragraph. It is worth between $15,001 and $50,000, not $50,001 and $100,000.