Federal Reserve Chair Janet Yellen has an expensive stamp collection.

According to Yellen's latest financial disclosure, her stamp collection is worth $15,001-$50,000. Yellen, however, did not appear to sell any stamps, as income related to that asset was listed as none, or less than $201.

The disclosure form requires Yellen to list her assets and income, though the amount of each asset held is put into a range bucket, not given a precise figure.

A report from Martin Crutsinger at the AP said the value of Yellen's assets — which include stakes in ConocoPhillips, Pfizer, and Office Depot common stock, as well as a number of stock and bond funds — rose 8% in 2013.

Yellen did not appear to hold any social media or biotechnology stocks in her portfolio.

Here's Yellen's full disclosure, which was posted on Scribd by The New York Times' Binyamin Appelbaum.