Market value alone is not enough. Under Rule 12b-2, a company must also have been subject to Exchange Act reporting under Section 13(a) or 15(d) for at least twelve calendar months, must have filed at least one annual report, and must not qualify as a smaller reporting company under that definition's revenue test. The test is run once a year, as of fiscal year end, using the float measured at the end of the second quarter.
The status drives the calendar. General Instruction A of Form 10-K gives a large accelerated filer 60 days after fiscal year end to file its annual report, compared with 75 days for an accelerated filer and 90 for everyone else. Form 10-Q allows 40 days after quarter end, the same window accelerated filers get. The new status applies starting with the annual report for the year in which it was determined.
Dropping out takes more than dipping below $700 million. A large accelerated filer keeps the label until its float falls below $560 million; between $60 million and $560 million it steps down to accelerated filer, and below $60 million — or on qualifying under the smaller reporting company revenue test — it becomes a non-accelerated filer. That buffer keeps companies near the line from flipping categories every year.