Why American Pacific Borates, NAB, Perenti, & Xero are tumbling lower

The S&P/ASX 200 Index (ASX: XJO) looks set to continue its poor run on Thursday. In afternoon trade, the benchmark index is down 0.6% to 7,000.8 points.

Four ASX shares that have fallen more than most today are listed below. Here’s why they are tumbling lower:

American Pacific Borates…