How Do New IPOs Get Added to the Russell Indexes?

Russell adds new IPOs to its US indexes through a quarterly review in March, June, September, and December, and, since May 26, 2026, very large underwritten IPOs can also join after the close of the fifth trading day following their listing. The June and December additions take effect together with the semi-annual reconstitution, which in 2026 means after the close on Friday, December 11. As of October 2026, IPOs that start trading between August 3 and October 30 are the ones in scope for that December review.

How often does Russell add IPOs?

Russell reviews IPOs every quarter. According to the Russell US Indexes methodology, eligible IPOs are added on a quarterly schedule, and FTSE Russell says it does this so that new additions to the market are reflected between reconstitution periods.

The timing differs by month. March and September additions are announced on the Friday four weeks before implementation and take effect after the close on the third Friday of the month. June and December are different: the IPO additions are implemented together with the semi-annual reconstitution, on the fourth Friday of June and the second Friday of December, and are announced five weeks ahead for June and four weeks ahead for December. The details of the December event are in hi2morrow's guide to when the Russell reconstitution takes place in December 2026.

FTSE Russell publishes the results on its IPO additions page. The third-quarter 2026 reports came out on September 4, while the second- and fourth-quarter lists are folded into the reconstitution files. For scale, the June 2026 report counted 24 IPO additions, 5 in the Russell 1000, 17 in the Russell 2000, and 2 in the Russell Microcap ex Russell 2000, all effective after the close on June 26.

Which IPOs qualify for the quarterly addition?

An IPO qualifies for a quarterly addition if it began trading in the review window, meets all of the regular Russell eligibility requirements, and is large enough. The methodology considers IPOs that price and trade between the rank days of two consecutive review cycles, so an IPO is considered at the first review after it lists, not on its first day.

For additions outside the reconstitution months, two tests apply on the IPO rank day. The IPO must have priced and traded, and its total market capitalization must be larger than that of the market-adjusted smallest company in the Russell 3000E as of the most recent June reconstitution. The size breakpoints are market-adjusted between reconstitutions, so the exact dollar figure for a given quarter is not fixed in advance. How rank day and the minimum size work in the regular reconstitution is covered in hi2morrow's explainer on how Russell rank day works.

Once an IPO qualifies, it is slotted by total market capitalization into the size ranges set at the last reconstitution, adjusted for market movement since then. Its growth and value split comes from the average style probability of its sub-sector, and outside reconstitution it is treated as fully dynamic in the Russell Stability Indexes.

When are IPOs added in December 2026?

IPOs that began trading between August 3 and October 30, 2026 are reviewed for the December reconstitution, and those that qualify are added after the close on Friday, December 11, 2026. FTSE Russell's November 2025 schedule notice lists the IPO review period as August 3 to October 30 and sets the IPO market cap cut-off at October 30, the last business day of the month. It also lists November 13 as the date indicative review files are circulated, November 30 as the start of lockdown, and December 14 as the first open under the new membership.

The window and the cut-off are set by the notice, so a listing in October is still in play as of this writing. What nobody can know before the November 13 files is which specific IPOs will be on the list, because that depends on each company's market capitalization and eligibility at the cut-off. The notice also carries the usual caveat that dates may change and clients will be told if they do.

December has one more feature that matters for new listings. In the reconstitution, new additions, including IPOs added between rank days, receive fresh style probabilities, while most existing members keep their June values. The methodology also says that IPOs entering during a reconstitution have their style probabilities calculated in full, whereas IPOs added in a quarterly review take the average of their sub-sector.

What is IPO fast entry, and when did it start?

Fast entry lets a very large underwritten IPO join the Russell indexes after the close of the fifth trading day following its listing, without waiting for the next quarterly review. LSEG's announcement of the change says the rule took effect on May 26, 2026, with the stated aim of letting index-tracking funds take part in large IPOs closer to the listing date.

The size test is tied to the Russell Top 500. An IPO is eligible if its market capitalization exceeds the market-adjusted Top 500 breakpoint from the previous reconstitution. For this test, the market cap is calculated from the shares offered in the IPO, including any over-allotment confirmed before the first trading day, and the closing price of the first trading day. Shares taken up by restricted holders are excluded.

Free float and voting rights must still be at least 5%. The methodology allows an IPO below 5% if lock-up expirations are estimated to lift it above the minimum within 12 months of inclusion, but the locked-up shares themselves are not added at entry. FTSE Russell confirms the exact effective date by notice. In the June 2026 IPO additions report, one of the 24 additions was announced under fast entry on June 12.

Why do some IPOs wait for the next review?

Some IPOs wait because the index has to know how many shares are actually available to the public, and because fast entry has built-in limits. The rules distinguish by IPO structure. For an underwritten IPO, free float is based on the post-IPO shareholder structure if that is public in the filings before the IPO rank date, and otherwise on the shares offered to the public.

Variable-price, best-efforts, and direct-listing IPOs face a stricter step. They are considered at the next quarterly review only if, by the IPO cut-off, a public disclosure confirms the shareholder structure after the IPO. If it is missing, the evaluation is deferred to the following review, and if it is still missing then, the company is evaluated at reconstitution only. These structures are also excluded from fast entry altogether. SPAC mergers follow their own separate rules, which depend on lock-up expiry.

Lockdown is the other cause of delay. A fast-entry addition whose effective date would fall inside the lockdown before a semi-annual reconstitution is implemented with the scheduled rebalance instead. For December 2026, lockdown begins on November 30. Lock-ups matter too: locked-up shares count toward free float only after the lock-up expires, and green-shoe shares only after the option is exercised and publicly confirmed.

What does an IPO addition mean for trading?

For a trader, an index addition is mostly a timing and mechanics question. The addition takes effect after the close on a known date, and products that track the index have a reason to match the new membership at that close. That is an interpretation of how index tracking works, not something the methodology states, and the size of the flow in any particular stock is not published in advance.

In practice, the closing auction on the effective date can be busier than usual in names being added, with the same rules as on any other day. hi2morrow's guide to why stock volume spikes at 3:50 p.m. ET explains the imbalance publication and the on-close order cutoffs that apply. An addition is a rule-based event, not a forecast of how the stock will trade afterward, and it says nothing about whether a company is a good business. How a new listing gets its first price in the first place is a separate topic, covered in hi2morrow's guide to why a U.S. IPO doesn't start trading at 9:30 a.m.

A worked example with ABC and XYZ

Suppose ABC, a hypothetical underwritten IPO, begins trading on Nasdaq on September 15, 2026. That is too late for the September addition and inside the December window of August 3 to October 30. ABC's shareholder structure after the IPO is disclosed in its filings before the October 30 rank date, so its free float is based on that structure. At the October 30 cut-off, it has a total market capitalization of $900 million, which in this example places it within the Russell 2000 size range. ABC meets the other eligibility requirements.

Under those assumptions, ABC would appear in the indicative files circulated on November 13, be added after the close on December 11, and trade as a Russell 2000 member from the open on December 14. As a December addition, it would also receive its own style probabilities. The price and share count are invented, and nothing here implies that a real IPO will be added.

Now take XYZ, another hypothetical underwritten IPO that lists on a Thursday and closes its first day with a market capitalization well above the Top 500 breakpoint, using the shares offered in the IPO. XYZ would be eligible for fast entry and, under the rule, be added after the close of the fifth trading day following its listing, which lands in the following week whether or not the listing day itself is counted as the first of the five. The published rule summaries do not spell out that counting, so the date that matters is the one FTSE Russell confirms by notice. If that date fell inside the lockdown starting November 30, XYZ would instead join with the December 11 rebalance.

Alexander Styopin's professional view: the most useful habit is to keep the three paths apart. A listing is not "added to Russell" on its first day, and the phrase can mean a quarterly review, the December reconstitution, or fast entry, each with a different date and a different test. Before reacting to a headline that a new listing is joining an index, check which path applies, what the effective date is, and whether the closing auction on that date is where you actually plan to trade. The rest is calendar work, and the calendar is public.

Educational material only. Not investment advice. Index schedules and methodology can change, and order types and on-close cutoffs vary by broker and exchange.

Author: Alexander Styopin, hi2morrow analyst and economist with 25 years of experience in the US stock market