The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →The Nasdaq-100 has scheduled quarterly rebalances in March, June, September and December. December also contains the index’s annual reconstitution, when Nasdaq reviews membership and can add or remove companies. Rebalancing changes weights; reconstitution changes who is in the index.
The schedule at a glance
Nasdaq maintains the Nasdaq-100 on a recurring calendar rather than waiting for a single annual event. There are four scheduled rebalance dates each year. The March, June and September events adjust constituent weights, while the December event adjusts weights and incorporates the annual review of eligible companies.
As an Amazon Associate I earn from qualifying purchases.
| Scheduled event | Reference data | Announcement | When changes become effective | Membership review? |
|---|---|---|---|---|
| March rebalance | Last trading day of February | After the close on the sixth trading day before the effective date | Market open on the first trading day after the third Friday in March | No routine annual review |
| June rebalance | Last trading day of May | After the close on the sixth trading day before the effective date | Market open on the first trading day after the third Friday in June | No routine annual review |
| September rebalance | Last trading day of August | After the close on the sixth trading day before the effective date | Market open on the first trading day after the third Friday in September | No routine annual review |
| December rebalance and reconstitution | Last trading day of November | After the close on the sixth trading day before the effective date | Market open on the first trading day after the third Friday in December | Yes; annual eligibility and membership review |
The dates are defined by trading days, not fixed calendar dates. A holiday can therefore change the exact day on which Nasdaq announces or implements a change. The effective event occurs at the market open, so the first session with the new index composition begins after the relevant third Friday.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Rebalance and reconstitution are different actions
What a rebalance does
A rebalance recalculates the weights of companies already represented in the index under Nasdaq’s methodology. It is a maintenance event: a constituent can receive a larger or smaller target weight even when it remains an index member. The March, June and September events are scheduled rebalances, and December includes one as well.
#1 Best Overall
- [Ultra-Lightweight Ear Buds Designed for Small Ears] Each earbud weighs only 3.7g and features a compact, ergonomic in-ear design made especially for small ears. Secure, low-profile, and comfortable for workouts, all-day wear or overnight sleeping.The ultra-slim profile sits flush in your ear with no hard edges poking or rubbing, so you can even sleep on your side without discomfort.
- [Immersive Stereo Sound with TOZO OrigX Technology] TOZO OrigX tuning delivers clear vocals, balanced mids, and natural stereo sound for music, podcasts, and videos.
- [Long Battery Life for Daily Use] Get up to 7 hours of playtime on a single charge, with up to 32 hours total using the charging case—ideal for workdays, commuting, and extended listening sessions.
- [Bluetooth 5.3 & Stable Connection] Bluetooth 5.3 provides fast pairing, stable wireless performance, and reduced dropouts as you move around home or office.
- [Deep Bass with Clear Vocals] High-performance drivers produce punchy bass while keeping vocals clean and detailed for everyday listening.
The Nasdaq-100 uses a modified market-capitalization weighting scheme. Larger companies generally have more influence than smaller constituents, but the index rules modify a pure market-cap-weighted result. A quarterly rebalance is therefore not an instruction to make every holding the same size.
What a reconstitution does
The annual reconstitution is the membership review conducted in December. Nasdaq evaluates companies that meet the index’s eligibility requirements and can replace companies that no longer qualify with eligible companies that rank higher under the methodology. The 2024 Nasdaq announcement described the index as 100 of the largest non-financial companies listed on Nasdaq and confirmed the annual December review.
A company can consequently experience two different types of change in December: it may remain in the index but receive a revised weight, or it may enter or leave the index altogether. The membership decision and the weight calculation are related but distinct parts of the December process.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →How the calendar works in practice
1. Nasdaq gathers the reference data
Each quarter uses the last trading day of the preceding month as its reference point: February for March, May for June, August for September and November for December. The annual reconstitution also uses the last trading day of November. This means the holdings displayed immediately before an event do not necessarily reflect the final inputs used to calculate the new portfolio.
2. Nasdaq announces the changes
The scheduled announcement is made after the market closes on the sixth trading day before the effective date. Investors therefore have a published list of additions, deletions and weight changes before the new composition starts trading. Because the rule counts trading days, the announcement date moves when exchanges are closed for holidays.
Rank #2
- 【IP68 Waterproof Multifunctinal Smart Watch】Torjalph fitness activity tracker smart watch is IP68 waterproof technology ,you can wear it when swimming,handwashing,it's rain-proof which means that you perform multiple exercise modes outside without worrying about sweat or rain corroding your fitness smart watch,and this watch equipped with a 230 mAh large capacity battery magnetic charging ,and this sports activity tracker watch can be used 5-7 days If fully charged.
- 【Larger 1.83'' Full Screen Watch & Multi-dial Selection】1.83 inch full HD color touch screen smart watch for men / women provides excellent 240*284 resolution image quality ,This Bluetooth smart watch offers a better touch experience and remarkable immersion and ,more than 200 watch faces for you to choose from App"Da Fit ", you can change the dial style according to your mood to wear keeping the world on your wrist
- 【Accurate Activity Tracker Smart Watch 】sports watch activity tracker uses sweat and dust resistant breathable silicone strap, our Fitness Tracker Smart Watch for Android iOS Phones supports 12 sports modes,walking,running,bicycle,swimming,badminton,basketball,football,rope skipping. This bluetooth calls smart watch for men women is lightweight and stylish, bringing more convenient and relaxing sports experience while also providing more protection.
- 【Your 24 Hour Personal Daily Health Monitor】Fitness watch for women men full touch screen IP67 waterproof bluetooth smartwatch for Android iOS Phones with heart rate blood pressure monitor multifunction Andriod smart watch with steps counter sleep monitor sports fitness watch, monitoring blood oxygen saturation allows you to understand your physical condition in real time to track fitness progress ,to know your health status in time.
- 【More Functions Bluetooth Call Smart Watch】This fitness activity smart watch full screen for iPhone and Android phones includes a bunch of new features including:The bluetooth smart watch can hang up the phone, receive and display WhatsAPP /Text /Facebook /Twitter /Messenger reminder.Support sedentary reminder, alarm clock, stopwatch, timer,weather information,music control, remote camera control compatible with Android 5.0 and above or iOS 9.0 and above smartphones.
3. The new composition takes effect
Changes become effective at the market open on the first trading day following the relevant month’s third Friday. Index-tracking funds must have their portfolios aligned with the new targets by that point, although their order execution can occur over a period around the effective session.
4. The index remains in force until the next scheduled event
Between scheduled events, ordinary market-price movements change each company’s market value and therefore its percentage of the index. The next rebalance recalculates the target weights using the applicable data and rules; it is not a daily equalization process.
Why Nasdaq can hold an unscheduled special rebalance
Quarterly maintenance is not the only mechanism available. Nasdaq may conduct a special rebalance when concentration becomes excessive under the index rules. The stated triggers are a company exceeding a 24% weight, or companies with weights above 4.5% collectively exceeding 48%.
Those thresholds are concentration safeguards, not forecasts of what will happen to a particular stock. A special rebalance can redistribute weight among constituents outside the normal March, June, September or December timetable. Whether Nasdaq invokes the provision depends on the measured index composition and the methodology in force at that time.
What happens inside an index-tracking fund
Funds must trade to match the target
An ETF or other portfolio that tracks the Nasdaq-100 has to adjust when the index changes. It may buy a newly added company, sell a deletion, increase a reduced holding, or trim a company whose target weight falls. The trades are portfolio-maintenance transactions, not a discretionary decision that the manager expects one security to outperform.
Rank #3
- [Low Noise High Fidelity] New bee guitar cord with 22AWG oxygen-free-copper center conductors provides enhanced signal transfer, the PVC insulation material and the high-density stranded copper double shield provide noise rejection for quiet operation
- [Ideal for Choice] New bee 1/4 straight and right angle metal connectors, ensures a secure connection in any instrument, pedal, or amp jack. L shape great fro on stage guitar stands
- [Wide Compatible] Suitable for mixer, power amplifier, microphone, effector, decoder, equalizer, electoronic organ, electric guitar, electric bass and other electronic equipments. Widely used in the installation of smart home, karaoke speaker, professional stage audio, etc
- [Easy Disassemble] Making incidental repairs quick and easy! Very nice, flexible cable
- [Dont Hesite to Order] 24 hours customer services and professional technology team are standing by
Invesco states that “The Fund and the Index are rebalanced quarterly and reconstituted annually.” That description explains why a Nasdaq-100-tracking product changes holdings in March, June, September and December, with December also accommodating the membership review. QQQ is designed to provide investment results that, before expenses, correspond to Nasdaq-100 performance. Invesco positions QQQM for long-term exposure, while investors should still check each product’s current documents for fees, structure and trading characteristics.
Trading can create implementation costs
Adjustments can generate brokerage costs, bid-ask spread costs, market-impact costs and temporary differences between a fund’s return and the index’s theoretical return. A fund may trade before, at or after the effective open depending on its rules, liquidity and execution process. The index calculation itself does not pay these costs; investors in the tracking vehicle bear them indirectly through the fund’s expenses and tracking difference.
The scale of the ecosystem matters
As of December 2025, Nasdaq said the index underpinned more than 200 tracking products with over $600 billion in assets under management globally. A large tracking ecosystem means that many portfolios may need to respond to the same published change, but it does not guarantee that every manager will trade at the same time or in exactly the same way.
Does every rebalance make the stocks equal weight?
No. The Nasdaq-100 remains based on modified market capitalization. A rebalance updates the weights produced by that methodology; it does not reset each of the 100 positions to 1%.
This distinction matters because the index can remain concentrated in its largest companies. If the biggest constituents rise faster than the rest of the index, their market values can increase their influence between rebalances. A later rebalance may reduce or otherwise adjust those weights under the rules, but it does not turn the index into an equal-weight portfolio.
Recommended Free Tools
Rank #4
- Digital Family Calendar: BSIMB digital calendar wall touch screen puts an end to your chaotic life. Designed for busy families, the digital calendar keeps you organised and in step with your family. Assign different colours and tasks to each family member to make family scheduling easier and more intuitive.
- Easy Setup and Auto-Sync: Plug in, connect to WLAN and auto-syn your electric calendar in minutes. Digital wall calendar compatible with Google calendar, iCloud calendar, Outlook calendar, Cozi calendar and Yahoo calendar. Add events directly on the device or through the ecalendar app. Electronic calendar stays current whether you're at work or traveling—no manual updates needed.
- All-In-One Home Assistant: Smart calendar builds habits and encourage independence with personalised chores. Display daily meal plan to reduce the daily ‘What's for dinner?’ stress. To-do lists keep track of everything you want. Turning chores into valuable achievements with stars and rewards, making life easier and more enjoyable.
- Manage Anytime Anywhere: BSIMB electronic calendar for family stay connected with the powerful ecalendar app. Access and manage your digital wall calendar anytime, anywhere with free features like stars & rewards, photo screensaver, chore charts, meals plans, to-do lists etc. Electronic planner paid features like Magic Import tailor advanced tools for users with special needs.
- Stay in Touch with Loved Ones: Share photos or videos from your phone to electronic wall calendar with app, instantly update your life moment, and keep in touch with your family, especially those who are far away; you can also surprise your smart calendar digital wall by sending him a wish card; it's also great for keeping tech-illiterate elders in touch with the youngsters.
Investors who want to understand their exposure should look at the current constituent weights and sector concentration rather than assume that the word “rebalance” means diversification into equal-sized positions.
Do Nasdaq-100 additions automatically rise in price?
No automatic price increase follows from an addition. An incoming company can receive buying interest from index-tracking funds, but the market may anticipate the announcement, other investors may sell into that demand, and the company’s own news or valuation may dominate the effect.
The same reasoning applies to deletions. A deletion can create selling by trackers, yet its price response depends on expectations, liquidity, broader market conditions and the reasons it left the index. The methodology determines which portfolios must be changed; it does not determine a guaranteed return for the affected security.
There is also no single universal return statistic for every Nasdaq-100 rebalance. The securities, size of the weight changes, market regime and trading conditions differ from one event to the next. Treating an addition as a mechanical buy signal ignores those variables.
Free tools Windows power users keep installed
One-click scans. No signup required.
What the schedule means for different investors
Long-term index investors
If you own a tracking fund for long-term exposure, the quarterly timetable is mainly an explanation of why holdings and weights change over time. You generally do not need to place a trade solely because Nasdaq has published a rebalance. Your fund’s mandate handles the adjustment, while your decision should remain tied to allocation, risk tolerance, taxes and time horizon.
Investors buying or selling near an effective date
Near an announcement or effective open, spreads and short-term volatility can differ from normal conditions in the affected securities. An investor placing a market order should understand that the execution price can move while funds and other participants reposition. Limit orders, patience and checking normal liquidity can reduce the risk of an unexpectedly poor fill, but none guarantees a particular price.
Investors comparing tracking vehicles
When comparing ways to obtain Nasdaq-100 exposure, evaluate the attributes that determine how closely your result follows the index:
- Trading liquidity: A frequently traded vehicle may be easier to enter or exit, especially for large or short-term orders.
- Long-term holding orientation: A product marketed for long-term exposure may have a different practical use from one commonly used for active trading.
- Expense ratio and tracking difference: Fees and implementation results reduce the return relative to the index’s published level.
- Bid-ask spread: The spread is an immediate trading cost that can matter more for frequent transactions.
- Tax treatment: The account type, distributions and your jurisdiction can change the after-tax result.
- Concentration: Modified-cap weighting can leave the largest constituents with substantial influence.
Current fees, spreads and tracking results are product-specific and can change. Confirm them in the issuer’s current documents rather than relying on an old comparison.
A practical way to follow a Nasdaq-100 event
- Identify the event. Determine whether it is the March, June, September or December scheduled date, or an announced special rebalance.
- Mark the reference date. Use the last trading day of February, May, August or November for the corresponding quarterly event.
- Check the announcement. Look for Nasdaq’s publication after the close on the sixth trading day before the effective date.
- Separate weight changes from membership changes. A weight adjustment is not the same as an addition or deletion; December can contain both.
- Check the effective session. The new composition begins at the market open on the first trading day after the third Friday of the month.
- Review your own vehicle. Read the fund’s notice, holdings file and prospectus to see how it implements the index change and what costs may apply.
- Avoid assuming an outcome. Use the event to understand exposure and portfolio maintenance, not to assume that an addition will rise or a deletion will fall.
A simple timeline example
Suppose an investor is watching the September event. Nasdaq uses the last trading day of August as the reference date. After the close on the sixth trading day before the effective date, it announces the revised weights and any membership changes that apply. The changes then take effect at the market open on the first trading day after September’s third Friday. A tracking fund prepares its trades around that effective session, and its holdings afterward should reflect the new index targets, subject to normal implementation differences.
The same sequence applies in March, June and December. December adds the annual eligibility review, so investors should expect the possibility of additions and deletions as well as ordinary weight changes.
Common mistakes to avoid
- Calling December the only rebalance: December is the annual reconstitution month, but the index also rebalances in March, June and September.
- Confusing rebalancing with reconstitution: Rebalancing changes weights; reconstitution reviews membership.
- Expecting equal weights: The index uses modified market-cap weighting, not a 1%-per-company reset.
- Using calendar dates instead of trading dates: Announcements and effective sessions are defined with trading-day rules.
- Assuming every tracker trades identically: Funds can differ in execution timing, costs and resulting tracking difference.
- Treating an addition as a guaranteed winner: Price effects depend on expectations, liquidity, the affected securities and the wider market.
- Ignoring concentration: A Nasdaq-100 fund can remain heavily influenced by its largest constituents even after a rebalance.
What investors can reasonably conclude
The calendar provides a predictable maintenance rhythm: four scheduled quarterly rebalances, with the December event combined with an annual membership review. It tells you when index-tracking portfolios are expected to update and why a fund’s holdings may change even when you take no action.
It does not provide a reliable short-term trading signal. Nasdaq’s rules specify eligibility, weights and timing, while prices and returns are determined by the securities and the market. Investors can use the schedule to monitor concentration, understand fund transactions and verify that a vehicle is following its mandate, but they should not treat the rebalance itself as a promise of outperformance.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchWindows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallQuick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
