Backpack Value went down $100 for unknown reason

[The Earbud Crusader]

For some reason, my backpack value dropped by $100 + without me making any trades or any of my items dropping... It says my backpack never exceeded $700 on the chart but I remember it did. 

 

http://backpack.tf/profiles/76561198062802524

 

Thanks!

[Stargatius]

Probably it's because refined went down.

[The Earbud Crusader]

ah, that explains it. thank you!

[Cave]

The refined man...

0,01$ (P.RM) Can drop alot from a high-tier backpack.