A “hyper-rally” in Commonwealth Bank shares that has helped push the Australian sharemarket to a fresh peak despite concerns about the outlook for iron ore will be tested when the bank’s popular dividend reinvestment scheme wraps up on Friday.

The benchmark S&P/ASX 200 Index claimed a fresh all-time high at the close of 8140.9 points on Tuesday, extending its rally this year to 6.6 per cent. Much of that has been underpinned by the nation’s largest bank, which accounts for almost 10 per cent of the gauge and has soared 26 per cent this year.