Australian shares were flat with a negative bias on Tuesday's close, amid expectations for a rally in US stock markets next year.

The S&P/ASX 200 was little changed to close at 8,717.1.

Investors expect another 9% average gain for the S&P 500 in 2026, Bloomberg reported.

They are also keeping an eye open for the Federal Reserve's minutes of its December meeting due later, the report added.

The weakness in equities "is a reversal from last week when tech stocks led on the way up," said Joe Mazzola, head trading and derivatives strategist at Charles Schwab.

However, it "doesn't appear connected to any single fundamental factor," Mazzola added.

In company news, IPD Group (ASX:IPG) agreed to acquire Platinum Cables, a provider of cable products to the mining sector, for AU$37.5 million in cash and shares. Shares of the company rose past 4% at market close and earlier hit a 52-week high.

DroneShield (ASX:DRO) received an AU$8.2 million contract from an in-country reseller for delivery to a western military end-customer.

Lastly, Origin Energy (ASX:ORG) said UK-based utility software platform Kraken Technologies is raising $1 billion in its first standalone equity raise to support the formal separation from Octopus Energy in 2026. Shares of the company rose past 1% at market close.