Fortescue Ltd (ASX: FMG) shares are sliding today.

Shares in the S&P/ASX 200 Index (ASX: XJO) mining stock closed yesterday trading for $15.89. In morning trade on Friday, shares are changing hands for $15.62 apiece, down 1.7%. That sees the share price down a painful 42% over 12 months.

For some context, the ASX 200 is up 0.2% today and up 6.2% over a year.

Though we shouldn't forget Fortescue's juicy dividends here. Over the past 12 months, Fortescue shares have delivered $1.39 each in fully franked dividends.

What's been happening with the ASX 200 miner?

There's been quite a lot of news impacting Fortescue shares this week.

Before market open on Thursday, the miner reported on significant delays in getting its Iron Bridge project on its intended production track.

Fortescue said it is now aiming to achieve Iron Bridge's nameplate capacity of 22 million tonnes a year in FY 2028. The company had originally hoped to achieve that milestone this September.

Despite the setback, management expects Iron Bridge to still achieve its FY 2025 market guidance for iron ore shipments and operating costs.

In other major news likely impacting Fortescue shares today, after market close yesterday, the ASX 200 miner announced a major leadership shakeup. The company reported that Mark Hutchinson will retire as Energy CEO, while Shelley Robertson will exit her position as Fortescue's chief operating officer.

Dino Otranto, CEO of Metals and Operations, will assume an expanded role on their departures.

Fortescue shares: Buy, hold, sell?

With all of this background in mind, the analysts at Macquarie Group Ltd (ASX: MQG) ran their slide rule over Fortescue shares.

In a research report released late Thursday, Macquarie said it expects lower total sales in the years ahead, with the Iron Bridge ramp-up slower than expected.

According to the broker, "Incorporating FMG's revised guidance, we cut FY26/27/28 total sales by ~1% (Iron bridge cut 20%/7%/5%)".

Macquarie said its own long-term estimate for Iron Bridge is 20.4 million tonnes a year, 7% less than Fortescue's guidance of 22 million tonnes.

The broker also doesn't expect Fortescue shares will get much of a boost from any fixed cost base relief at the project.

According to Macquarie:

FMG carries a large fixed cost base at iron bridge with its processing and sunk mobile plant capex being sub-optimally utilised. Therefore, we expect limited cost out relating to the deferred ramp up, with savings likely to be spent on increased maintenance and rectification works. Therefore, we assume the volume cuts flow directly to the bottom line.

Macquarie maintained its neutral recommendation on the ASX 200 miner.

"The delay of Iron Bridge ramp up, which faced multiple technical challenges since commissioning, was disappointing," the broker said. "However, this was offset by the leadership update with the indicated re-focus on metals division a key positive."

Macquarie has a $15.00 12-month price target on Fortescue shares.