Hard to say without seeing your computer (screenshot) of your My collection page. I had an issue where my collection didn't look right. Then I realized everything except banknotes were filtered out.
I was going to suggest collapse in gold and silver prices, but they have gone up again. My gold has gone from $59k to $63.5k in one week, although gold price only climbed on Friday, likely it was a slumping local currency.
Another reason could be a catalogue value “recalibration”.
I love coins. Especially silver, gold and anything really old.
Member of the Royal Numismatic Society of New Zealand and the Auckland Numismatic Society
And have you checked your filter settings at the top right or not? I have seen no changes to my ‘My value’.
Maybe some items or a high value single item have moved categories (if you don't use the ‘all collections’, ‘all types’ filters this could influence your values).
I don't know how large your collection is (value wise) but if I look at my value from the export (Buying power) the My values in my collection is about 8% lower. The Estimate is about the same. Most probably has to do with the decline of the US Dollar vs. Euro, about 7% from end of September to today.
