Financial experts analyzing historical data from 2004 to 2025 have found that selling stocks at market highs to buy back in over 12 months underperforms staying fully invested nearly 80 percent of the time, resulting in an average return lag of nearly 6.9 percentage points.
As the Taiwan Stock Exchange climbed upward and overall market valuations reached relative highs, a popular investment strategy emerged advising investors to sell stocks to reduce exposure and then reinvest in gradual tranches over six to 12 months. Financial commentator Qingliujun examined historical data to test whether this defensive maneuver actually protects portfolios, and the findings challenge conventional wisdom according to the outlet reported. Rather than avoiding downturns, retreating to the sidelines often creates a significant performance drag.
Historical Backtest Data on Dollar-Cost Averaging Versus Full Exposure
To evaluate the feasibility of exiting the market during high valuations, the analysis utilized historical data from the Yuanta Taiwan Top 50 ETF (0050) alongside the Taiwan market’s cyclically adjusted price-to-earnings ratio, known as CAPE. The study evaluated 253 valid 12-month starting periods from July 2004 through July 2005, comparing two distinct approaches: maintaining complete equity exposure through lump-sum or fully invested positions versus converting holdings to cash and deploying them through 12-month dollar-cost averaging.
Out of 253 test cycles, the phased-in buying strategy lagged behind continuous full-exposure holding in 197 instances. That failure rate reaches 77.87 percent, with an average performance deficit of 6.90 percentage points as detailed in the research data. Investors who attempted to time the market by selling high and buying back gradually ultimately underperformed those who simply maintained their positions.
The Fallacy of High Valuation and Market Correction Timing
A core misconception among retail investors is that an expensive market valuation guarantees an immediate downturn. However, market valuation and market trajectory represent two entirely separate dynamics.
Even when sorting the dataset by CAPE valuation into four quartiles and focusing exclusively on the most expensive 25 percent of historical periods, the staged-reinvestment strategy failed to reverse its underperformance, lagging by an average of 6.63 percentage points. High CAPE ratios signal lower long-term expected future returns, but they do not predict a correction over the immediate subsequent months. When expensive markets continue climbing, holding uninvested cash on the sidelines generates a distinct cash drag according to market commentary.
Dual Decision-Making Traps and Portfolio Rebalancing Solutions
Selling existing shares with the intention of slowly repurchasing forces an investor to execute two extraordinarily difficult decisions simultaneously: determining that the current price is too high to hold, and correctly timing when to re-enter the market. When prices continue rising after a sale, investors frequently become paralyzed by hesitation, waiting for a pullback that may not materialize while sitting on sidelined cash.
Rather than attempting to time market peaks or liquidate portfolios out of valuation anxiety, long-term investors are advised to rely on asset allocation rebalancing. Rebalancing functions as a risk-management tool that adjusts asset weightings back to their intended targets when appreciation pushes them past established thresholds. Effective long-term strategies depend on building an asset allocation robust enough to withstand a steep market drop of 20 to 30 percent without forcing panic selling.
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