When a new website costs more than it earns
A new website should be a commercial accelerator for a retail brand. For one ecommerce business, launching well into peak Q4 trading, it became the opposite. Launched in October 2025, and within three months, 80% of transactional traffic had gone. Over £100,000 in revenue lost during the high-demand December period, which should have been their strongest of the year.
Visually, the site looked better, the catalogue was rebuilt around two core journey’s for retail buyers and invetsors. All parties, developers and the stakeholders were proud of it on launch day. But the site migration was masking a challenge that would take months to formulate the true performance picture
What actually happened
The build was solid. The design was considered. The development team worked hard and delivered what was asked of them as per the scope of work and signed-off brief.
The problem was for this ecommerce retailer is that they believed their organic search and LLM performance would be treated as something that would carry over automatically from the old site to the new one. There was no SEO involved, it was handled by the developers. During a site migration, performance very rarely aligns that way as there are usually multiple changes that create a reconsideration, relevance checks and re-rank. Just because you rank well on the old site doesn’t mean you will when you move to a new platform and template design.
Product pages that had ranked consistently for years were restructured during the build. Redirects were missed. Informational content driving thousands of sessions every month was overlooked during the migration process and disappeared from Google entirely. A rendering issue that went undetected before launch quietly dismantled three months of peak trading performance before anyone understood what was happening.
By the time the scale of the problem became clear, the reconsideration phase had passed. There was no natural bounce back. Recovery work began by the developers, but without a clear understanding of “what went wrong” a lot of the time the fixes are surface level and do not have the depth that an technial SEO expert would have.
Why these stories are not rare, but they never get told
This is far from an isolated case. It is one of the most common outcomes of a website migration handled without dedicated SEO input, and it rarely gets discussed publicly because it is uncomfortable for everyone involved.
A business invests significantly in a new website. Months of planning, design and development. A launch day with genuine pride across the team. And then a slow, confusing period of watching performance decline while trying to understand why the previous site worked better.
The development agency responds with genuine effort, working to identify and fix the issues. The challenge is that website migrations contain hidden variables that require specialist knowledge to anticipate. There are always factors that are invisible until they have already caused damage. You do not know what you do not know.
Making the invisible visible
The role of an SEO migration specialist is to surface those hidden variables before they become commercial problems.
At POLARIS, the pre-launch process is built around making every factor that affects organic performance visible and validated before a site goes live. Crawl behaviour, redirect integrity, rendering performance, content continuity, structured data, page speed, internal linking architecture. Each area checked against the baseline of the existing site so that nothing critical is carried across incorrectly or left behind.
A site with fundamental technical SEO issues does not go live. That is the standard, and it is the only standard that protects commercial performance at launch.
The cost of recovery
Recovering lost rankings is slow work. Rebuilding redirect structures, reclaiming lost equity, identifying and resolving rendering issues after the fact all take time and resource. In almost every case, the cost of recovery exceeds the cost of getting it right before launch.
For this business, recovery is progressing. Rankings are returning. But the revenue lost during peak Q4 trading does not come back. That window closed.
What to consider if you are planning a new website
A new website is one of the most significant commercial decisions a business makes online. The build, the design and the development all matter. So does the organic search continuity that sits beneath all of it.
Involving an SEO partner from the earliest stages of a migration, before the architecture is set, before the content decisions are made, before the redirects are mapped, is the point at which specialist input has the most impact and the lowest cost.
The question for any business planning a new site is straightforward. The investment in getting it right from the start is known and manageable. The cost of recovering from a migration that goes wrong is open ended.
If you want to understand what a pre-launch SEO migration process covers, the POLARIS website migration checklist sets out every critical checkpoint from planning through to post-launch monitoring. You can find it here: https://www.polarisagency.com/marketing-insights/website-migration-checklist/
Next in our SEO Migration series
Next up: Migrations need an expert SEO presence from the start. Otherwise, information arcitectures are inheritied around the business not the customer. The next article covers the key challenges with this approach, what signals to watch and how to distinguish company langauge from target customer search intent.
