If you work with Chinese suppliers, you have certainly received a number of messages about increasing prices of raw materials, like the following:
"Dear [buyer name]
The prices of [main raw materials in their product] have increased a lot recently, so we have to increase the price of your product to X.XX USD per piece. We are sorry for the inconvenience caused.
Best regards,[Supplier name]"
How did you react? Did you see it as a lame excuse from the manufacturer, trying to justify an increase of their margin? Sometimes this is true, but not always...
There are several things you can do to verify if increases in product prices are legitimate: read them all in the Full article on qualityinspection.org