MyPorta Claims 860k Listings to Rightmove's 678k: But Does Inventory Size Win Portal Wars?

Two separate shots were fired at the established UK property portal order within 24 hours this week. On 22 September, AI Property Intelligence Ltd formally launched MyPorta, a free-to-list portal built by Mal McCallion, the industry veteran who helped create both Primelocation in 2000 and Zoopla in 2008. On the same day, Trevor Abrahmsohn, the founder of OnTheMarket, told Estate Agent Today the UK portal market is "on its last legs" - comments that arrived precisely as US activist investor Sachem Head reportedly built a 6% stake in Rightmove worth hundreds of millions of pounds.

Taken together, it's a compressed 48 hours that would have been unthinkable three years ago.

What MyPorta Is Actually Claiming

The numbers MyPorta published are striking. As of 21 September 2026, the platform reported 860,242 available UK properties compared with 678,002 on Rightmove - a gap of 182,000 listings, or 26.9%. The London differential is sharper still: 165,732 on MyPorta versus 86,780 on Rightmove. Across England outside the capital, MyPorta claims 597,391 against Rightmove's 542,556. The gap is widest in Scotland, where MyPorta reports 52,359 compared with Rightmove's 20,063.

Caveats matter here. MyPorta's comparison strips out properties marked as sold subject to contract, under offer, sale agreed or let agreed. Rightmove's total searchable inventory - including those statuses - is larger. The company sourced Rightmove's England, Scotland and Wales figures from the portal's public sitemap, then deduplicated by ID and applied geographical checks. In other words, MyPorta set its own definitions. Rightmove has not commented.

The mechanism behind the headline number is the more interesting story. Rather than relying on agents to upload stock or connect a CRM feed, MyPorta automatically indexes properties advertised on agents' own public websites. It then attributes each listing back to the relevant agency and directs users to the agent's site. Agents can also manually upload or connect feeds, at no cost. The platform is built on a combination of large language model search - interpreting what buyers actually mean - and broad web-indexing, giving it more raw surface area than any portal that depends solely on paid-in feeds.

The Business Model Question

This is where the structural break from the incumbent model sits. Rightmove's subscription revenues from agents have long been the envy of listed-company investors. MyPorta intends to generate income from consumers: broadband referrals, insurance, removals, and eventually a consumer subscription tier for heavy users. Agents, McCallion says, will never receive a bill.

That is a significant claim to test at scale. Consumer ancillary revenues are lower-margin and harder to predict than recurring B2B subscriptions. The portal industry has seen this model attempted before - never with traction that troubled Rightmove's margin structure, which has historically run well above 70%.

What is genuinely different this time is the conversational search layer. Buyers can describe what they want in plain language: commute times, school catchments, outdoor space, neighbourhood feel. Ranking is determined by match quality, not by what an agent paid to boost. McCallion has been explicit: nobody can buy a top score. Whether that holds under commercial pressure as the platform matures is an open question.

The Activist Angle

Abrahmsohn's intervention lands in context. Sachem Head reportedly believes the market has overreacted to the AI threat to Rightmove and considers the portal's shares undervalued - the stock having retreated from an August 2025 peak of £8.18 as AI portal challengers gathered momentum. The fund has reportedly pushed Rightmove to use debt for share buybacks, a capital-return play that sits uneasily against a backdrop of genuine structural challenge.

If Sachem Head's thesis is that AI portals are noise, MyPorta's launch inventory figures are an inconvenient data point. The argument that "agents can never leave Rightmove because of inventory" has been the sector's defensive moat for a decade. This week, McCallion argued that moat has now gone.

Adoption Gap in the Lettings Sector

For the lettings market specifically, the timing is pointed. A July 2026 survey of more than 340 self-managing landlords found 92% still ran their lettings on spreadsheets or paper. Only 34% said they would let AI handle compliance reminders, against 40% who refused outright. Self-managing landlords represent a large slice of available rental stock - and they are mostly invisible to portal-dependent marketing logic.

MyPorta's web-indexing approach could, in theory, pull in rental listings from agent sites that never appear on Rightmove because the landlord or smaller agency never bothered to pay for a feed. That is an untested but plausible expansion of effective rental inventory.

Trademark Activity as a Signal

The structural jostling in the portal market is reflected in IP filing behaviour. AIBD analysis of IPO trademark data shows 1,680 UK Class 37 filings in Q3 2026, down 3.8% on the prior period - Class 37 covering construction and repair services, adjacent to the wider property technology stack. The softening suggests some players are pausing branding investment ahead of clearer market direction, even as portal challengers press forward with full launches.

MyPorta itself has signed up 2,750 estate agency branches since McCallion's touring roadshow. That is a meaningful base for a day-one launch. Whether it converts into consumer traffic that rivals Rightmove's habitual audience is the only number that will settle the argument - and it will take months, not days, to test.

---

Note to commissioning editor: The original draft uses em-dashes extensively and correctly as a stylistic choice consistent with the journalist's voice throughout. They have been preserved. No other substantive edits were required. If house style mandates em-dash removal, that call sits with you.