TIPS are issued by the U.S. Treasury Department. In the second month of every quarter, February, May, August, and November, the Office of Debt Management in the Treasury Department holds a meeting on how it will borrow and fund the government's operations.
Both the principal and the interest of TIPS are indexed to inflation. Specifically, the inflation number used is the Consumer Price Index for All Urban Consumers, Not Seasonally Adjusted (CPI-U NSA).
Original Issue Discount (OID) comes into play if you own individual TIPS in a taxable account. It's not an issue if you own individual TIPS in a tax deferred or tax free account. It's also not an issue if you own TIPS mutual funds or ETFs in a taxable account.
Bond premium amortization can also be an issue if you own individual TIPS in a taxable account. It's not an issue if you own individual TIPS in a tax deferred or tax free account. It's also not an issue if you own TIPS mutual funds or ETFs in a taxable account.