S&P/ASX 300 Index (ASX: XKO) shares are in the green on Friday, up 0.03% to 8,529 points at the time of writing.

Over the FY25 period, ASX 300 shares rose by 9.94%.

They provided total gross returns, including dividends, of 13.74% in FY25.This was on par with the performance of the benchmark S&P/ASX 200 Index (ASX: XJO).

ASX 200 shares rose by 9.97% and delivered total gross returns of 13.81% in FY25.

In this article, we present one ASX 300 share that Stuart Bromley of Medallion Financial Group rates a buy and one that's a sell.

Buy or sell this ASX 300 blue-chip healthcare giant?

CSL Ltd (ASX: CSL)

CSL remains the largest healthcare stock on the Aussie market despite a terrible year for its share price in FY25.

The CSL share price fell 18.65% from $295.21 on 28 June 2024 to $240.15 on 30 June 2025.

CSL is an Australian biotech and the world's biggest blood collector.

Its Seqirus division is one of the world's largest influenza vaccine companies. Its Behring division focuses on rare and serious diseases.

In 2022, CSL made a major entry into renal disease treatment through its $11.7 billion acquisition of Vifor Pharma.

CSL shares have a long and impressive track record for price growth, as the following chart shows.

COVID was a major interruption for the business, and the CSL share price has drifted sideways over the past few years.

Many analysts have had a buy rating on CSL for years. They've been waiting for this ASX 300 blue-chip share to find its momentum again.

Bromley also has a buy rating on CSL shares.

He explains this rating (courtesy The Bull):

The company lifted net profit after tax (NPAT) by 7 per cent at constant currency in the first half of fiscal year 2025.

The dividend increased by 16 per cent in Australian currency.

In our view, the company is trading at a significant discount and provides an opportunity to enter an Australian powerhouse at an attractive valuation.

Buy the dip or burn this ASX 300 retail share?

Domino's Pizza Enterprises (ASX: DMP)

What a week for Domino's Pizza shares.

The Domino's Pizza share price lost a quarter of its market value in one fell swoop on Wednesday after news of the CEO's exit.

Domino's shares slumped 26% to an intraday low of $14.80 as the market digested Mark van Dyck's plan to leave on 23 December.

He's less than a year into the job, having only taken the helm in November 2024 upon Don Meij's retirement after 22 years in the job.

So his resignation was unwelcome news for investors amid a 79% share price slump since September 2021 and a recent period of significant operational reset for the company.

He's already stepped down as a director, and Domino's chair and largest shareholder, Jack Cowin, has taken the reins while they search for a new CEO.

Cowin said Domino's new strategic foundations were "now firmly in place".

This includes raising franchisee profitability, simplifying operations, identifying and implementing cost savings, and improving execution.

Cowin said he will collaborate with van Dyck and the executive team over the coming months.

Before news of van Dyck's resignation, Bromley said he was unable to identify a catalyst for a meaningful recovery in the Domino's share price.

That's why he has a sell rating on Domino's shares.

Bromley said:

Group earnings before interest and tax of $100.6 million in the first half of fiscal year 2025 were down 6.7 per cent on the prior corresponding period.

Network sales were down 2.9 per cent and same store sales fell 0.6 per cent.

Ongoing leadership changes and persistent underperformance in key international markets, such as Japan and Europe, have further weighed on profitability.

Bromley points out that the Domino's share price has fallen from $58.26 on 8 January 2024 to $17.71 at the time of writing.

On top of weak sales momentum, we're unable to identify a catalyst that will lead to a meaningful recovery – at least in the short term.

Cowin conducted a video call with institutional investors yesterday.