It is not an index or a survey. It is a recurring outright purchase of long-dated Treasury Inflation-Protected Securities (TIPS) in the 7.5 to 30 year sector. The Open Market Trading Desk of the Federal Reserve Bank of New York runs it.
It acts for the System Open Market Account (SOMA) under Federal Open Market Committee (FOMC) directives. It buys outstanding United States securities in the secondary market from primary dealers, for themselves and customers. It reports offered and accepted par amounts with per-issue detail. It is not a new Treasury auction, a buyback, a holdings level, or a demand gauge. Small-value operations are readiness tests, not policy moves.