The sharemarket opened lower on Monday, paring some of last week’s gains as the US’ back-and-forth approach to tariffs kept traders cautious and as a wave of selling hit James Hardie Industries.

The S&P/ASX 200 slipped 0.2 per cent, or by 12.2 points, to 7919 in the first 10 minutes of trading. The All Ordinaries Index slipped 0.2 per cent.

James Hardie Industries dragged, shedding 10.4 per cent after striking a deal to merge with NYSE-listed AZEK in a cash and share transaction worth $US8.8 billion ($14 billion).