In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to start the week with a disappointing decline. At the time of writing, the benchmark index is down 1.2% to 8,652 points.

Four ASX shares that are not letting that hold them back are listed below. Here's why they are rising:

Amaero Ltd (ASX: 3DA)

The Amaero share price is up 5.5% to 47 cents. Investors have been buying the high-value refractory and titanium alloy powders producer's shares following the release of its quarterly update. Amaero reported revenue of $1.489 million. This comprises approximately $1 million from powder sales and $483,000 from Powder Metallurgy Hot Isostatic Pressing (PM-HIP) manufacturing. CEO, Hank J. Holland, commented: "We are pleased to report a milestone quarter that positions Amaero for transformational growth as we move into FY2026. The commissioning of our second advanced atomizer in Tennessee, on schedule, underscores our commitment to building a secure, sovereign, scalable, and traceable supply chain for high-value refractory and titanium alloy powders."

AMP Ltd (ASX: AMP)

The AMP share price is up 9% to $1.67. This has been driven by the release of the financial services company's second quarter update. AMP reported a 63.2% increase in Platforms net cashflows to $1,565 million. It also revealed that its Superannuation & Investments reached positive net cashflows for the quarter of $33 million. This was the first time since 2017 that this has been achieved.

Block Inc (ASX: XYZ)

The Block Inc share price is up 11% to $121.75. This follows a strong gain by the payments giant's NYSE listed shares on Wall Street on Friday. The catalyst for this was news that the Afterpay and Cash App owner's shares will be added to the benchmark S&P 500 index after Hess Corp (NYSE: HES) was acquired by energy giant Exxon Mobil (NYSE: XOM).

South32 Ltd (ASX: S32)

The South32 share price is up 5% to $3.03. Investors have been buying this mining giant's shares following the release of its fourth quarter and full year update. Summarising its performance, South32's CEO, Graham Kerr, said: "We delivered another strong quarter of operating performance, exceeding the Group's FY25 production guidance, driven by annual production growth of 20% in copper and 6% in aluminium." Another positive was that management revealed that operating unit costs are expected to be in line with its current guidance.