SEC Form 485BPOS Explained: The Annual Fund Prospectus Update

Form 485BPOS is the post-effective amendment nearly every mutual fund and ETF files at least once a year to keep its prospectus current. It is filed under Securities Act Rule 485(b), which lets a fund make non-material changes effective immediately on filing, instead of waiting out the longer review period that applies to material ones.

This guide covers what counts as non-material under Rule 485(b), what a 485BPOS actually contains, how it differs from 485APOS and 485BXT, and how to pull the fee table out of one as structured data.

What Form 485BPOS is for

Every registered open-end fund, and most insurance separate accounts and unit investment trusts, must keep a current prospectus under Section 10(a)(3) of the Securities Act. A prospectus goes stale as soon as its financial statements age past the SEC's timing rules, so funds file a post-effective amendment to refresh it, typically once a year.

Rule 485 under the Securities Act splits post-effective amendments into two paths depending on whether the changes are material:

• Rule 485(b), filed as 485BPOS, is for amendments the fund itself determines are not material: the annual update of financial statements, performance and fee figures, routine disclosure edits. It is effective on filing, or on a date the fund designates.
• Rule 485(a), filed as 485APOS, is for amendments the fund considers material enough that the SEC staff might want to look at first: a new fund series, a new investment strategy, a material change to fees or risk disclosure. It only becomes effective 60 days after filing, or 75 days when it adds a new series, unless the SEC accelerates or delays that date.

485BPOS does not mean a fund is launching something new

It is tempting to treat any filing in the 485 family as a sign that a fund complex is doing something new, but that reads the rule backwards. Because 485BPOS exists specifically for non-material changes, the single most common thing it reports is the routine, expected annual update: refreshed performance numbers, an updated fee table, and the same strategy as last year.

If you are trying to spot a new fund series or a real change in strategy before it launches, the filing to watch is 485APOS, not 485BPOS. The 60 or 75 day gap between a 485APOS and its effective date is exactly the window during which a new series or a material change is visible on EDGAR but not yet live. A 485BPOS carrying a brand-new series usually means the fund already went through that 485APOS review and is now filing the amendment that actually brings it into effect.

485BPOS vs. 485APOS vs. 485BXT

A single new series can produce all three over time: a 485APOS to start the SEC review clock, one or more 485BXT filings if the fund needs more time before launch, and finally the 485BPOS (or the 485APOS becoming effective on its own) that brings the prospectus live.

What is inside a 485BPOS filing

A 485BPOS generally carries the fund's complete, current registration statement rather than a marked-up diff from the prior year:

• Prospectus, with the fund's objective, principal strategies, principal risks, the fee table and expense example, and past performance.
• Statement of additional information (SAI), covering trustees, their compensation, fund policies and service providers in more detail than the prospectus.
• Financial highlights, per-share data for the fund's last several years.
• Part C, exhibits such as the investment advisory agreement, distribution agreement and any material contracts.
• XBRL risk/return tagging, which machine-tags the fee table and performance figures using the SEC's risk/return summary taxonomy.

Because it carries the whole registration statement, a 485BPOS is the most complete single snapshot of a fund's current terms, which is also why it is the filing the Fund Fees API and other fund data products read from. The 485BPOS dataset page lists coverage dates and every field SecFeed returns from it, alongside the 485APOS dataset for the slower, material-change counterpart.

Reading the fee table in code

SecFeed parses the XBRL-tagged fee table out of each fund's latest 485BPOS (or other current registration filing) by series and share class, instead of leaving you to read the prospectus PDF.

curl "https://secfeedapi.com/v1/fund-fees?cik=36405" \
  -H "Authorization: Bearer YOUR_API_KEY"

A response row looks like this for one share class:

{
  "series": "EXAMPLE GROWTH FUND",
  "class": "Class A",
  "managementFee": 0.0065,
  "distribution12b1Fee": 0.0025,
  "otherExpenses": 0.0015,
  "totalAnnualExpenses": 0.0105,
  "netExpenseRatio": 0.0099,
  "expenseExample": {"1yr": 103, "3yr": 324, "5yr": 562, "10yr": 1250}
}

To see the filing that fee table came from, including every other series and class in the same trust, query the trust's filings directly and filter for form type:

from secfeed import Client

sf = Client("YOUR_API_KEY")
filings = sf.search('formType:"485BPOS"', cik="36405", size=5)
for f in filings:
    print(f["filedAt"], f["accessionNo"])

Frequently asked questions

Does 485BPOS mean a fund changed something material?

No. Rule 485(b) exists specifically for changes a fund has determined are non-material. A material change, such as a new strategy or a new series, is filed as 485APOS instead, which has to clear a 60 or 75 day review window before it takes effect.

How often is a 485BPOS filed?

At least once a year, to keep the prospectus current under Section 10(a)(3) of the Securities Act. Funds also file one whenever they need to make a non-material update outside the annual cycle.

What is a 485BXT?

A 485BXT is a post-effective amendment filed under Rule 485(b)(1)(iii) solely to push back the effective date of an earlier amendment, usually a 485APOS still awaiting a new fund's launch. It does not contain a new prospectus itself.

Is a 485BPOS reviewed by the SEC before it goes live?

No. It is effective immediately on filing or on a date the fund chooses. The SEC can still review it afterward and require changes, which is the reverse of the pre-effectiveness review that applies to a 485APOS.

Where do I find a fund's current prospectus?

The most recent 485BPOS (or, for a fund that has not yet gone through its first annual update, the 485APOS or N-1A it launched under) holds the current, complete prospectus. SEC filing types covers how fund registration statements fit alongside the other forms public companies file.