Sector-by-Sector Bullish Percent Index Analysis

A bullish percent index (BPI) measured sector-by-sector reveals which parts of the market are gaining strength and which are lagging, offering a granular view of market breadth. By comparing the percentage of stocks in each sector trading above their 10-week moving average, traders can spot sector-specific leadership, hidden weakness, and potential rotation signals that the broad-market BPI might mask.

From broad-market BPI to sector detail

The standard bullish percent index measures the percentage of stocks in a major index (S&P 500, Russell 2000, or Nasdaq 100) trading above their 10-week moving average. When the broad BPI climbs to 80% or above, it signals overbought conditions; when it drops to 20% or below, it signals oversold conditions. Values between 30% and 70% are considered neutral.

But the broad BPI hides crucial information: it’s an average. A broad BPI of 50% could mean that all sectors are evenly split, or it could mask a situation where technology stocks are at 90% bullish while healthcare stocks are at 10%—a major divergence with very different implications.

Sector-by-sector BPI analysis breaks open this black box. By calculating BPI separately for each major sector—financials, energy, consumer discretionary, industrials, healthcare, information technology, utilities, real estate, materials, communication services, and consumer staples—a trader gains visibility into which sectors are genuinely strong and which are weak. This is especially useful during market cycle transitions when different sectors lead and lag.

How to interpret sector BPI divergence

Divergence is the signal that makes sector BPI analysis valuable. Suppose the broad BPI is rising toward 70%, suggesting a maturing rally. If technology and communication services BPIs are at 85% while financials and industrials are stuck at 40%, the market is not in uniform strength. Instead, growth and momentum sectors are overheated while value and cyclical sectors are lagging. This divergence often precedes a rotation: as investors gradually shift from tech into beaten-down value, the tech BPI will roll over while the value BPI climbs. Catching that transition early is a major tactical edge.

Conversely, when all sector BPIs are climbing and remaining above 60%, the market is in “risk-on” mode with broad participation. This is a much healthier rally than one driven by a handful of mega-cap stocks. Broad participation suggests the rally is more durable.

Sector BPI in downtrends and bear markets

Sector BPI becomes even more useful when the broad market is under pressure. During the early stages of a bear market, some sectors (classically defensive ones like utilities, consumer staples, and healthcare) hold up better than others (cyclicals like consumer discretionary and industrials). By watching sector BPI, a trader or fund manager can identify which sectors to cut first and which to hang on to.

If consumer discretionary BPI collapses to 20% while healthcare BPI remains at 60%, it signals that the market is rotating into defensive mode. Investors who recognize this shift early can trim cyclical exposure and add defensive holdings before a broader selloff accelerates.

Similarly, near the bottom of a bear market, some sectors (often those tied to recovery—industrials, materials, energy) will rebound first, lifting their BPI from 20% back toward 40% and 50%. These early improvers are often the best performers in the subsequent bull market. A disciplined trader can use this as a signal to start rotating back into risk.

Multi-sector divergence as a warning

One of the most reliable warning signals is negative divergence: the broad BPI is still elevated, but several major sectors’ BPIs are deteriorating. This suggests the rally is narrowing and losing breadth.

Example: In late 2021, the broad S&P 500 BPI remained above 60%, but beneath the surface, a cluster of sectors—including financials, industrials, and materials—had rolled over, their BPIs falling to 40% or 50%. Meanwhile, technology and communication services kept the overall BPI afloat at 70%. This divergence was a warning that the broad market’s strength was fragile and concentrated. When technology finally stumbled in early 2022, there was little support from other sectors, and the decline was sharp.

By tracking sector BPI divergences in real time, a portfolio manager can reduce concentration risk and hedge sectors that are weakening before the broad market catches up.

Sector rotations and BPI clusters

Market cycles often follow a predictable sector rotation: as the economy heats up, cyclical sectors (technology, consumer discretionary, industrials, materials) outperform; as the economy cools, defensive sectors (utilities, consumer staples, healthcare) outperform. Sector BPI readings can help time these rotations.

Early in a cycle, when economic growth is accelerating, watch for tech and discretionary BPIs to climb faster than staples and utility BPIs. If the gap widens (tech at 75%, staples at 45%), the cycle is in “risk-on” mode. Conversely, if the staples and utility BPIs climb toward 70% while tech BPI stays at 50%, the market is shifting into a defensive posture, often a sign that growth is slowing and recession risk is rising.

Energy and materials BPIs are particularly sensitive to commodity prices and growth expectations. A sharp rise in these sectors’ BPIs alongside broad-market strength often signals “healthy” inflation-adjusted growth; a collapse signals stagflation or deep recession fears.

Screening for relative strength

One practical application is to screen for the sector with the highest BPI each week or month. If technology BPI is at 85% while all other sectors are in the 50–65% range, technology is the relative strength leader. This doesn’t mean technology will continue to outperform (overextension can lead to pullbacks), but it does flag where the action is concentrated.

Conversely, the sector with the lowest BPI is often an opportunity for mean reversion. If real estate BPI has sagged to 25% while the broad BPI is at 55%, real estate is oversold and may bounce back sharply once conditions stabilize. This is especially true if other sectors have already bounced, suggesting real estate is simply lagging.

Combining sector BPI with other breadth metrics

Sector BPI is most powerful when used alongside other breadth indicators. The advance-decline line (the cumulative total of stocks advancing minus declining) can corroborate sector BPI signals: if both the broad BPI and the advance-decline line are rising, the rally is confirmed; if the advance-decline line is falling while BPI is still high, the rally is becoming narrow and fragile.

Similarly, pairing sector BPI with moving averages and price-based technicals (support, resistance, trendlines) helps filter out false signals. A sector BPI at 75% is more actionable if the sector’s price index is also above its 50-week moving average and has not yet hit overhead resistance.

Common pitfalls

The main trap is over-interpreting short-term BPI spikes. A sector BPI can surge from 40% to 70% in a single strong week without signaling a genuine, multi-week shift in sentiment. Smoothing the BPI with a 4- or 8-week moving average helps filter noise and reveals true structural changes.

Another pitfall is ignoring volume. A sector BPI that rises passively (few stocks participating, low volume) is less reliable than one that climbs on heavy volume, which signals genuine conviction.

Finally, sector BPI must be context-dependent. A financials BPI of 60% is a green flag when interest rates are rising (rising rates help bank profitability), but a red flag when rates are falling sharply (falling rates compress lending margins).

See also