Lucerne, Switzerland—Swiss federal tax authorities have informed Gubelin Gem Lab that its non-Swiss clients of the lab are no longer subject to the value-added tax (VAT) and will now save 7.6 percent on each invoice, the lab announced Friday.

The fee-slashing is due to the government's changed interpretation to the existing VAT law, which governs tax on exchanges.

The lab said the tax change had been in force since January of 2007, but it had only been informed about the revision this summer. As such, the lab said all foreign clients who have had business with Gubelin Gem Lab between Jan. 1, 2007 and August 2007 will be contacted by the lab in order to receive reimbursement for taxes paid during that period.