Reporting season and the recent tariff sell-off have been tough for a number of S&P/ASX 300 Index (ASX: XKO) shares. After looking through the carnage, I think there are a number of businesses that are too good to ignore.

Being able to buy exciting, quality companies at significantly cheaper prices is very appealing. Investing at lower valuations can make a big difference to the overall returns.

For example, if a business' share price was $10 and rose to $20 in five years, that'd be a strong return of 100% over five years.

If, in the first few months of that company's growth journey, it dropped 20% to $8 and someone invested at that point and it still reached $20, that'd be a rise of 150% from $8 to $20. In other words, it'd be an extra 50% return than buying at $10.

That's why sell-offs can be so appealing to buy great businesses. I'm not expecting the below two ASX 300 shares to double in five years, but I do believe they're now (very) underrated opportunities.

Brickworks Ltd (ASX: BKW)

The Brickworks share price is down 9% from 10 March 2025 and down 22% from 18 March 2024, as the chart below shows.

I'd suggest the 12-month decline has largely been triggered by weak building product demand in Australia and the US amid elevated interest rates. The company's outlook in the US has also been clouded by the growing tariff war between the US and Canada, Mexico, China, and the EU.

In my view, Brickworks' building product earnings are usually cyclical, so it's good to be opportunistic at weak points in the cycle.

The business has significant asset backing through its ownership of half of an industrial property trust, which is benefiting from additional warehouse completions and growing e-commerce demand. It also owns around a quarter of Washington H. Soul Pattinson and Co. Ltd (ASX: SOL), which is delivering long-term dividend and capital growth for Brickworks.

I think this ASX 300 share is significantly undervalued and can handily beat the ASX 300 over the next three years.

Audinate Ltd (ASX: AD8)

The Audinate share price has fallen over 30% since 18 February 2025, and in the last year, it has declined 70%, as the chart below shows.

This audio-visual-focused company provides the Dante IP networking solution, which it claims to be the worldwide leader in. It is used extensively in the professional live sound, commercial installation, broadcast, public address, and recording industries. It replaces analogue cables with just an ethernet cable.

Audinate said that its FY25 first-half result was impacted by excess inventory in the original equipment manufacturer (OEM) channel, which saw operating profit (EBITDA) fall by $9 million to $1 million, with revenue dropping 38% to US$18.9 million.

However, there are some positives I'll point to besides the lower valuation. For starters, the business is expecting a return to more typical order patterns in FY26 as inventory levels normalise.

It also saw the gross profit margin improve by 10.7 percentage points to 82.2%, thanks to a product mix shift towards higher-margin software-based implementations.

Audinate believes its outlook remains strong, supported by an installed base of over 6 million Dante devices, which is growing by more than 1 million each year.

The ASX 300 share is aiming for broader Dante audio adoption with an increasing range of products. It wants to accelerate Dante video with a growing acceptance and integration of its video solutions. Finally, the company wants to establish a software ecosystem for AV professionals.