The benchmark S&P/ASX200 index on Monday finished down 46.5 points, or 0.56 per cent, to 8,249.5, while the broader All Ordinaries fell 56.3 points, or 0.66 per cent, to 8,494.0.
The ASX200 has only had two other five-session losing streaks in 2024, in January and April.
Capital.com analyst Kyle Rodda said there was a degree of caution in markets at the start of a busy week of central bank meetings, especially over the Fed meeting on Wednesday (early Thursday, Australia time).
"While a cut is fully baked-in and the curve reflecting a high bar for a hawkish surprise, the meeting still represents a meaningful risk event, with the outcome potentially determining whether equities experience a Santa rally to close out what's been a very good year for the stock market," Mr Rodda wrote.
Eight of the ASX's 11 sectors finished lower, with consumer staples and financials slightly higher and utilities basically flat.
Materials/mining was the biggest mover, dropping 2.0 per cent as the price of iron ore fell amid weak demand from China.
BHP dropped 2.0 per cent to $40.35, Rio Tinto retreated 1.7 per cent to $118.64 and Fortescue subtracted 3.8 per cent to $18.74.
Goldminers also finished lower as the precious metal traded around $US2,653 an ounce, with Newmont falling 3.6 per cent and Evolution dropping 2.2 per cent.
The big four banks were a different story, all posting at least modest gains.
NAB and ANZ both climbed 0.2 per cent to, $37.64 and $29.19, respectively, while CBA grew 0.3 per cent to $157.64 and Westpac expanded 0.8 per cent to $32.41.
Insurance companies fared even better, with IAG adding 1.2 per cent and Suncorp rising 0.8 per cent per cent.
Cryptocurrencies were rallying, with bitcoin hitting an all-time high of $US106,350 ($A166,820) on Monday afternoon following renewed speculation US President-elect Donald Trump might establish a "strategic bitcoin reserve" on his first day in office.
In more traditional finance, the Australian dollar had rebounded slightly but was still near a 13-month low against its US counterpart, buying 63.71 US cents, from 63.58 US cents at Friday's ASX close.
ON THE ASX:
* The benchmark S&P/ASX200 index on Monday fell 46.5 points, or 0.56 per cent, at 8,249.5
* The broader All Ordinaries dropped 56.3 points, or 0.66 per cent, to 8,494
CURRENCY SNAPSHOT:
One Australian dollar buys:
* 63.71 US cents, from 63.58 US cents at Friday's ASX close
* 97.88 Japanese yen, from 97.26 Japanese yen
* 60.58 euro cents, from 60.78 euro cents
* 50.43 British pence, from 50.23 pence
* 110.26 NZ cents, from 110.38 NZ cents
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