If a subsidiary site starts under the group site's subdirectory and moves to its own domain next year when there is separate ad budget, what gets stuck if we decide now?

Conclusion first: most projects do not have to make a hard choice between a subdirectory and an independent domain; first check whether the brand is presented independently to the outside. For a piece of introductory content inside the group, with few updates and centrally operated by the group, a subdirectory is simpler; for those with an independent product line, an independent sales team, and a need for separate advertising and ICP filing, the earlier an independent domain is used, the less trouble later; a subdomain is a workable third option. Based on typical 2026 delivery experience, what a subdirectory saves upfront is mainly ICP filing and deployment time, typically one to three weeks; the cost is that when splitting later you need redirect mapping, reset the analytics baseline, and rebuild indexing accumulation. The boundary of applicability is: if the site only does group introduction and has no independent contracting or advertising needs, there is no need to force an independent domain; conversely, if the brand is presented independently and leads need to be measured separately, a subdirectory will slow down its own accumulation.

A subdirectory, a subdomain, and an independent domain differ in ownership, not in page appearance

Technically, these are three ways of ownership. A subdirectory opens a path under the main site's domain and shares the main site's domain, certificate, server, and ICP filing entity; a subdomain has its own DNS entry and can be deployed independently, but ICP filing and entity are usually still under the same domain; an independent domain is a complete set of independent accounts, ICP filing, certificates, analytics, and operations. To visitors the difference is small; to the delivery and operations teams, the difference centers on who has permission to change things, who bears renewals and ICP filing, and whether it can be split later.

A domain is a long-term asset. The cost of a wrong choice is often not the first-year domain fee, but whether you need to do 301s when splitting two or three years later, whether you need to reset the analytics baseline, and whether the subsite has to be reworked when the main site is redesigned. Based on typical 2026 project delivery experience, this kind of rework is usually counted in person-days and is more expensive than the ICP filing time saved at the beginning.

• Permissions: Publishing permission for a subdirectory is often held by group IT; a subsidiary may need to submit a ticket to change one sentence.
• ICP filing entity: An independent domain usually has independent ICP filing, and the entity information matches contracts and invoices.
• Analytics: Whether you can see your own visits and inquiries separately determines how you account for advertising later.
• Certificates and renewals: Every additional domain setup adds one expiry reminder and one owner.
• Redesign coupling: When the main site changes templates, the subdirectory almost inevitably has to change too.

Why this choice affects operations for the next two or three years

First, indexing and authority. A subdirectory naturally inherits the main domain's existing indexing base and trust; an independent domain cannot inherit this and must build from zero. It typically takes three to six months to see a difference in organic traffic (experience range), and the exact timing also depends on content volume and backlinks. A subdomain sits between the two: it has an independent indexing entry, and some signals from the main domain still pass through; it is common in brand-related scenarios where the business is relatively independent.

Next, the operations side. Ad landing pages, analytics baselines, and brand-term search all follow the domain. If a subsidiary needs to run external advertising independently, build its own brand terms, and sign contracts and issue invoices independently, putting it under a subdirectory will instead slow its own brand-term and landing-page accumulation: visitors remember a path rather than a brand, and ad reports are often merged into the main site's accounting, making it unclear which lead came from whom.

The boundary of a subdirectory is not technical but about ownership: who is responsible for ICP filing, who is responsible for renewals, and who has the right to change main site configuration. If these three things are not written into the delivery checklist, they are more likely to cause blockages later. A common case is that six months after launch, a section path needs to be changed; main site operations schedule it two weeks out, and the subsidiary's campaign can only wait.

• When the main site is redesigned, the subdirectory's navigation, footer, and breadcrumbs usually need to be reworked in sync.
• Login state and cookie sharing rules differ between subdomains and subdirectories; confirm in advance if membership or quote forms are involved.
• If migration involves a change of ICP filing entity, an information verification process is often required again.

Ask four questions first, then look at three constraints

Ask about the business first and discuss technology second, because the domain approach itself is reversible, but the cost of reversal rises quickly with content volume. The four questions set direction, and the three constraints set implementation; reversing the order easily turns into just counting money.

1. Whether the brand is exposed independently to the outside: Whether the website title, business cards, and exhibition materials use the group name or the subsidiary name.
2. Whether it is an independent entity: Whether contracts, invoices, and ICP filing need a separate set.
3. Whether there is an independent advertising and analytics need: Whether you need to view your own conversions and lead costs separately.
4. Content volume and update frequency: Within a few dozen pages, or with a product library, news, and ongoing updates.

• Budget: The extra cost of an independent domain is mainly the domain fee, certificate, and ICP filing wait time.
• Operations staffing: When no one manages certificates and servers, a subdirectory is more stable, and issues can go to the group.
• Whether it will be split within the next two years: If it will be split, set up URL rules and analytics dimensions well from the start.

Once the first two of the four items are set, the approach is basically locked in; the latter two affect implementation details rather than direction. If you count money first instead, a common consequence is saving the domain fee but spending several times more time later on redirects and analytics when splitting.

A checkable comparison of three options: cost, timeline, and who they fit

The ranges below are based on typical 2026 delivery experience. They vary with the main site's tech stack, group approval process, and ICP filing location, and should not be treated as a quote.

• Subdirectory: Domain cost is typically zero; development and configuration typically 0.5 to 2 person-days; launch speed depends on main site operations scheduling, typically a few days to two weeks; suitable for sections with little content and centralized group operations.
• Subdomain: Domain cost is typically zero; configuration plus certificate is about 1 to 2 person-days, and the certificate can be free or a paid certificate costing a few hundred yuan per year; ICP filing usually follows the main domain, and a common practice is to confirm the access method with the hosting provider first; suitable for brand-related business that needs independent deployment and independent analytics.
• Independent domain: Domain costs tens to a little over 100 yuan per year (typical range for .com); ICP filing typically 2 to 4 weeks; development, deployment, and integration testing typically 1 to 3 weeks; suitable for independent brands, independent sales teams, and entities that need separate advertising.

One item easily missed in comparison is the renewal owner. An independent domain means one more expiry reminder; domain, hosting, and certificate expiring at different times is a common failure point, so the delivery checklist should state who watches it and how far in advance to remind. Renewal and redemption rules can be checked against the registrar's and hosting provider's official documentation.

Where delivery commonly gets stuck: trade-offs under one constraint

A common combination in projects is: a tight budget, only two weeks until launch, and group IT unwilling to change main site server configuration for the subsite. In this case, forcing an independent domain means clearly not enough ICP filing time; going directly with a subdirectory means facing the fact that change permissions are not in your hands. A more stable approach is to launch the subdirectory option first, but separately document the URL rules, navigation hierarchy, and analytics events in the delivery document, and agree on a path mapping table for future splitting.

The result is no launch delay, and the cost is also concrete: when it really needs to be split into an independent domain six months later, a few early links with parameters were not standardized, adding about two days for redirects and item-by-item checks; rework is typically 1 to 3 person-days (experience range), not huge but easily missed. Conversely, if you plan for an independent domain from the start and reserve a path prefix, splitting usually only requires configuring 301s and migrating analytics, and the workload is much more controllable.

Applicable scenarios and boundaries

When a subdirectory is suitable

• The content is group introduction, branch contact information, and a small amount of business explanation, within a few dozen pages.
• There is no independent advertising budget, and no need to view conversion data separately.
• The group centrally operates domains, certificates, and servers, and the subsidiary has no dedicated staff.

When an independent domain is not necessary

If you are only making an introduction page for a business line, do not plan to update it within a year, and have no independent contracting entity, registering a separate domain often means taking on operations burden early: an extra set of ICP filing, an extra certificate, and an extra expiry reminder, with no obvious benefit. A common cost of treating a subdirectory as a cost-saving option is that one main site redesign forces the subsite to be reworked, and the cost of integration and revisions often exceeds the domain fee and ICP filing time saved at the beginning.

When to go independent as early as possible

• The brand is presented independently, and customers recognize the subsidiary name rather than the group name.
• There is an independent sales and contracting entity, and invoices and ICP filing need to correspond one-to-one.
• You need separate advertising and lead cost accounting.
• Content will keep growing to hundreds of pages, or there is structured content such as a product library or document downloads.

What counts as done properly: several checkable acceptance criteria

• Unified URL rules: They can be written into documentation and mapped one-to-one to the new domain later.
• Separable analytics: At minimum, visits and conversions can be viewed separately by path or subdomain.
• Checkable ICP filing information: The domain actually visited matches the ICP filing information, and footer information can be checked.
• Permission list assigned to named people: Who has publishing rights, who has configuration rights, and who is responsible for renewals.
• Split plan: Redirect method, retention period, and channels to notify are written clearly in advance.

A pass standard can be judged this way: ask a colleague who did not work on the project to read the delivery document; if they can clearly say where this subsite is hosted, who manages it, and how it will be split later, it is basically in place. Relevant details can be checked item by item against the platform's official documentation and the delivery acceptance checklist rather than from memory.

Frequently asked questions

Will a subdirectory drag down the main site's indexing and rankings?

Normally not. Only when the subdirectory has poor content quality, chaotic internal links, or generates a large number of duplicate pages could it affect the main site; it is more important to define the section structure and internal link rules clearly during delivery.

Can a subdirectory use Baidu and GA analytics separately?

Yes. A common approach is to create separate properties or use path filters to isolate subdirectory data. The key is to define the analytics scope before launch to avoid mixing it with main site data for a long time.

When splitting from a subdirectory to an independent domain, does the original content need to be rebuilt?

No rebuilding is needed, but you need one-to-one 301 mapping and must reset the analytics baseline. Data will fluctuate for a period after the split; this is common, and there is no need to rush to judge the results.

Which is more like an independent site, a subdomain or a subdirectory?

A subdomain has a relatively independent indexing entry, while a subdirectory is closer to being part of the main site. Which to choose mainly depends on whether the business needs independence; indexing preference is not the deciding factor.

At implementation, it is recommended to do one thing first: write the four items—brand, entity, advertising, and content volume—into one sentence, ask the client to confirm it, and then decide the technical form. If there is little content and the group centrally operates it, a subdirectory is simpler; if there is an independent brand and independent sales team, use an independent domain as early as possible. The costs and timelines in this article are given as experience ranges; actual ICP filing and approval times are subject to local and hosting provider rules.