Treasury yields extended their recent declines after a $22 billion auction of 30-year bonds attracted strong demand from investors. Thursday’s sale completed a successful round of auctions for the government,

The outcome of the auction will tell us something about how expensive borrowing will be for the government — and for the rest of us.

An auction of 10-year Treasury debt encountered strong interest from buyers, marking a fourth consecutive robust offering and helping to allay concern that demand for U.S. assets is declining. While it is routine for the Treasury Department to borrow to fund the government,