May 20, 2026

What Are The Russell 1000®, 2000®, and 3000® Indexes? How Often Are They Reconstituted? And Which Includes the Most Biotechs?

The Russell 1000®, Rusell 2000®, and Russell 3000® are indexes of the largest publicly traded U.S. companies. Russell indexes are a part of FTSE Russell group, which also produces such benchmarks as the FTSE 100.

The Russell indexes are widely followed by tracker funds and as such, inclusion in one of them, or even better, promotion between them, is typically a positive event for a biotech’s stock price.

Understanding the difference between the Russell 1000, Russell 2000, and Russell 3000 – and how reconstitution works – is essential for any public biotech navigating the capital markets.

What are the Russell 1000, Russell 2000, and Russell 3000?

Index	What it Tracks	Company Size	Approximate # of Stocks	Market Coverage
Russell 1000	Large- & mid-cap companies	Mega-cap to upper mid-cap	~1,000	~90% of U.S. market cap
Russell 2000	Small-cap companies	Smaller growth/value names	~2,000	~8-10% of U.S. market cap
Russell 3000	The broad U.S. equity market	Large to small	~3,000	~98% of investable U.S. market

Source: Russell Indexes

The Russell indices are rules-based benchmarks designed to represent the U.S. equity market across different company size segments. They are constructed entirely using market capitalization.

Russell 3000: This is the broadest index. It contains roughly the largest 3,000 publicly traded U.S. companies and represents the overwhelming majority of investable U.S. equity market value.

Russell 1000: The top 1,000 companies by market cap inside the Russell 3000. These are large- and mid-cap stocks – think Big Pharma, profitable medtechs, and the occasional mega-cap biotech.

Russell 2000:  The remaining 2,000 smaller companies within the Russell 3000. This is the small-cap universe – and therefore where most clinical-stage biotechs live.

In mathematical terms: Russell 3000 = Russell 1000 + Russell 2000

Per our prior blog “How Do Biotechs Choose Their Stock Exchange Tickers, Why Are Most Biotech Tickers Four Letters Long, and How Far Ahead of an IPO Should Tickers Be Reserved?” you will recall that at the end of 2023 there were 2,272 companies listed on the NYSE and 3,432 on NASDAQ – making 5,704 listed companies in total.

As such – given that the Russell 3000 includes only the very largest 3,000 companies – the claim that it represents ~98% of the U.S. investable equity market rings true.

Which Russell index is most important for biotechs?

From a biotech perspective, the Russell 2000 is the most relevant index because it captures the early-stage growth companies that dominate the sector. That being said, many successful biotechs migrate upward to the Russell 1000 as their market caps grow.

Before we examine how that promotion takes place, let’s first talk about how the indexes are reconstituted.

How often are the Russell indexes reconstituted?

Historically, Russell indices underwent a full reconstitution once a year in June, a process widely referred to as “Russell Recon.”

During reconstitution:

• Companies were ranked by market capitalization.
• Constituents were reassigned between indices as appropriate.
• New IPOs that meet criteria were added.
• Others were removed.

Companies were ranked by total market capitalization using prices at a specified “rank day” (lately at the end of April), with other eligibility criteria necessitating:

• U.S. incorporation.
• A primary listing on a major U.S. exchange.
• Adequate liquidity and free float.

Once ranked, the largest 1,000 qualify for the Russell 1000, and the next 2,000 populate the Russell 2000. Companies that are too small – or fail eligibility screens – fall out of the index entirely. There is no discretion – it is all about math.

The annual June reconstitution created one of the highest-volume trading days in U.S. markets, because all the index-tracking funds had to rebalance simultaneously. Thus, in order to lessen the stampede (and avoid other problems associated with a single annual reconstitution date), the cadence was recently changed.   

FTSE Russell has announced plans to move to a semi-annual reconstitution schedule starting in 2026, adding a December update alongside the traditional June reshuffle.

Why does Russell inclusion matter?

While Russell inclusion does not validate a biotech’s science, it absolutely affects a company’s stock price.

According to FTSE Russell, at the end of 2024, $11.8 trillion in assets tracked or were benchmarked against Russell indexes, including a massive ecosystem of ETFs and passive mandates.

As such, when a biotech enters the Russell 2000:

• Passive funds must buy the company’s shares.
• Liquidity typically increases.
• Institutional ownership may broaden.

Conversely, when a company is removed, the opposite occurs.

Inclusion can signal a new stage of corporate maturity and can also be an important factor in the timing of any contemplated financings.

Moving from the Russell 2000 to the Russell 1000

Many companies falsely see moving from the Russell 2000 into the Russell 1000 as academic. It isn’t. It is a sign that the company’s investor base has changed and is likely to continue to change.

Russell 2000 investors tend to include:

• Small-cap specialists.
• High-turnover growth funds.
• Retail-heavy ETF flows.

Russell 1000 investors increasingly include:

• Large institutional allocators.
• Quantitative strategies.
• Multi-sector portfolio managers.

For a maturing biotech, graduating into the Russell 1000 often marks a transition from “story stock” to “portfolio component.”

That shift should be expected to influence:

• Messaging.
• Financial disclosure cadence.
• Investor targeting strategy.

How do biotechs get promoted to the Russell 1000?

Promotion isn’t about a single company milestone – it is about sustaining a market capitalization that clearly sits above the small-cap universe by (historically) late April (and in the future, late October, as well).

While the smallest company in the Russell 1000 recently had a market cap of $2-3B on rank day, the “breakpoint” (the point at which a Russell 2000-included company would be guaranteed of promotion to the Russell 1000) was around $5B. This is because the indexes have a policy of “banding” to prevent too much constituent churn.

Let’s talk about how banding works.

Rank Range	Typical Outcome
Top 900	Promoted to Russell 1000
~900-1100	Depends on prior membership (banding applies)
Below ~1100	Demoted to Russell 2000

Source: Russell Indexes

• If a company meets the eligibility criteria and has a market capitalization in the Top 900 of U.S. companies on rank day(s), it is included in the Russell 1000 (or promoted if it was previously part of the Russell 2000).
• If a company meets the eligibility criteria and has a market capitalization below the top 1100 U.S. companies on rank day(s), it is included in the Russell 2000 (subject to the caveat that there can only be 2000 companies in this index).
• Companies ranked between 900-1100 could be included in either index, but in practice, their assignment depends on whether they had previously been included in the Russell 1000 or Russell 2000.
  • Existing Russell 1000 members can have their market cap drift down into this zone and still stay in the index.
  • Likewise, Russell 2000 members in this zone will remain in the Russell 2000 until they clearly outperform.
  • As such, the market cap of the smallest Russell 1000 company can be much smaller than the market cap needed for a Russell 2000 company to gain promotion.

How many biotechs are in the Russell 1000 and Russell 2000?

Roughly 120–160 companies in the Russell 1000 fall into the following three sectors:

• Biotech
• Big Pharma + specialty pharma
• Life-science tools/diagnostics

Examples of Russell 1000 “Biotechs”

Name	Ticker	Mkt Cap ($)
Pfizer Inc	NYSE:PFE	156B
AbbVie Inc	NYSE:ABBV	409B
Amgen Inc	NASDAQ: AMGN	199B
Gilead Sciences Inc	NASDAQ: GILD	192B
Vertex Pharmaceuticals Inc	NASDAQ: VRTX	124B

Source: New Street Investor Relations

Meanwhile, roughly 280–350 companies in the Russell 2000 fall into:

• Biotech
• Pharma / specialty pharma
• Small-cap commercial biotech transitioning toward pharma

Examples of Russell 2000 “Biotechs”

Name	Ticker	Mkt Cap ($)
Xencor Inc	NASDAQ: XNCR	828M
Beam Therapeutics	NASDAQ: BEAM	2.8B
Fate Therapeutics	NASDAQ: FATE	144M
Arcutis Biotherapeutics	NASDAQ: ARQT	3.1B
Protagonist Therapeutics	NASDAQ: PTGX	5.1B

Source: New Street Investor Relations

From the above examples, it can clearly be seen that the Russell 2000 is far more relevant for development-stage biotechs.   

Practical IR considerations

When a biotech is included (or promoted) in a Russell index, it is customary to:

• Issue a press release marking the occasion.
• Message inclusion to a biotech’s Board.
• Factor the timing of any inclusion/promotion into the company’s financing plans.
• Review the company’s messaging and IR program to ensure it is appropriate for the biotech’s typical investor class (since promotion especially could be indicative of a shift in ownership style).