Rough Equal-Weight Blue-Chip Rebalancing
Cap concentration and rebalance blue chips toward buy-low, sell-high discipline
- Difficulty
- Moderate
- Time to result
- ~ongoing to results
- Steps
- 5
- Confidence
- 98%
This approach selects a defined universe of roughly 35 or 36 major companies, checks that industries are represented, and assigns approximately equal rather than capitalization-driven weights. A position cap—described as roughly four percent—prevents the largest market-cap companies from dominating the portfolio. Quarterly rebalancing trims securities that have risen far above their target weights and adds to those that have lagged, creating a mechanical buy-low, sell-high effect. Dividends are reinvested along the way. The process also documents how to handle mergers, acquisitions, spin-offs, and companies that fall outside the eligible size range. Its intended output is a more diversified megacap portfolio with less concentration and potentially lower volatility than a conventional capitalization-weighted index.
Origin
Extracted from Masters in Business, where John Montgomery explains Bridgeway's long-running blue-chip strategy and its alternative to market-cap weighting.
Core principles
- 01Market-cap weighting mechanically increases exposure to recent winners.
- 02Rough equal weighting limits dependence on the largest companies.
- 03Rebalancing systematically adds to laggards and trims outperformers.
- 04Industry representation matters even within a concentrated blue-chip universe.
- 05Rules and exception procedures preserve discipline during unusual events.
How to run it
- 1
Define the blue-chip universe
Identify approximately 35 or 36 of the largest eligible companies using consistent size and quality rules. Reassess eligibility at scheduled recomposition dates.
Pro tip Document the data source and cutoff rules.
Watch out Changing eligibility rules to favor current opinions undermines systematic discipline.
- 2
Check industry representation
Ensure the selected universe represents the intended range of industries. Correct accidental omissions before assigning weights.
Pro tip Define representation rules in advance.
Watch out Equal weighting alone does not prevent industry concentration.
- 3
Set rough equal weights
Allocate similar weights across holdings while allowing a small operating cushion. Apply a maximum-weight rule to prevent any company from dominating.
Pro tip Use explicit tolerance bands around target weights.
Watch out Loose definitions of roughly equal can allow concentration to return.
- 4
Rebalance quarterly
Trim positions that rose above their target ranges and add to positions that fell below them. Reinvest dividends according to the same allocation discipline.
Pro tip Use a fixed calendar to reduce emotional timing decisions.
Watch out Rebalancing too frequently can increase taxes and transaction costs.
- 5
Apply documented exceptions
Follow predetermined instructions for mergers, acquisitions, spin-offs, and companies that no longer meet eligibility rules. Record each exception and its resolution.
Pro tip Review exception rules after unusual events without rewriting them mid-event.
Watch out Ad hoc exceptions can turn a rules-based portfolio into discretionary market timing.
In the wild
A technology company grows to eight percent of a conventional market-cap index, while the strategy's maximum weight is approximately four percent. At the quarterly rebalance, the portfolio holds or trims the company near its capped target and redirects capital toward underweight eligible blue chips across other industries.
→ The portfolio retains exposure to the winner without allowing one company to dominate risk.
Common mistakes
Calling equal weight risk-free
The method changes the pattern of risk but does not eliminate losses. It can underperform when the very largest stocks lead the market.
Ignoring transaction costs
Quarterly turnover can reduce the rebalancing benefit, especially in illiquid securities or taxable accounts. Execution and tax effects must be monitored.
Abandoning the rule during a rally
The strategy is expected to lag when a few giant companies dominate returns. Chasing those winners destroys the intended concentration control.
Is it for you?
Best for
Long-term equity investors seeking diversified exposure to large blue-chip companies with systematic rebalancing.
Not ideal for
Investors whose mandate requires exact replication of a market-cap-weighted benchmark.
From the transcript
“market cap weighting is like a momentum strategy that you never rebalance, so you ride the wave up and then you write it down, and…”
“it's roughly equal weighted, which means you're always investing a little bit more in what's done poorly and harvesting a little bit from what's done…”
“Our rule of thumb is about four percent is the maximum weight and a strategy.”
From the episode
Factor-based Investing with John Montgomery
John Montgomery