Any sale would also allow Ocado to concentrate on its technology business of selling white-label robots and software to rivals worldwide – something that has been an increasing focus.
Both companies have committed to not changing the structure of the deal before its fifth anniversary in 2025. While insiders say there are no talks on the matter, Ocado and M&S could do a deal early if they wanted.
Clive Black, a retail analyst and house broker to M&S, says: “It’s not novel to expect a deal to be one of the next steps to think about”, but that it “remains to be seen at what price that happens at”.
One M&A banker said the cost for M&S will vary depending on how the pair’s relationship evolves, but that the £750m it paid initially was a “starting point”.
The deal has been transformative for M&S whose e-commerce offering had practically been non-existent, Stuart Machin, joint operating chief and head of its food business, told investors in October.
Not only has it helped secure better deals with suppliers, because it sells more of everything, but the pairing changed its customer base.
“We’re attracting new customers who didn’t shop with M&S, or M&S customers are switching to Ocado rather than other online competitors,” Machin said.
He added that the tie-up was yet to reach its full potential: “This is working for us today, but more importantly, this gives us a significant opportunity for the future.”
One challenge, however, is the pace of expansion. It currently takes Ocado about two years to build and install the robots, and it can only serve a set number of orders.
Nevertheless, the firm has been ramping up new site openings this year with hundreds of thousands of orders expected to go live.
M&S would also need to obtain financing if it decided to make an offer for the 50pc stake, and would have to improve its credit rating.
But credit agencies S&P and Moody’s have awarded M&S BB+ and Ba1 ratings respectively, still below investment grade which allows a company to borrow more cheaply.
The retailer, which is making progress with its most recent turnaround, stopped paying a dividend at the start of the pandemic and took out a Covid loan from the Government, which restricts payouts to shareholders. This has allowed it to save cash, which could improve its overall position financially.
When it comes to Ocado, retail pundits are split as to whether it could be tempted to offload its stake.
Those who know boss and co-founder Steiner say he has always had a soft spot for his white-label tech business, Ocado Solutions, while the grocery arm interests him less.
