PART 01
KOSPI 10-Year Data: Was January Really Profitable?
Truth of 'January Effect' verified with developer-crawled data
Jan Return
Over the last 10 years, KOSPI's January win rate is 60%. However, the average January return is 0.7%, which is not overwhelming compared to other months (April, November). 'It always goes up' is a myth.
Seasonality Heatmap
+0.7%
Jan-0.2%
Feb+0.5%
Mar+2.1%
Apr-0.8%
May+0.3%
Jun+1.2%
Jul-1.1%
Aug-0.5%
Sep+0.4%
Oct+1.8%
Nov+1.1%
DecApril and November are hotter than January.
Key Insight
"The January Effect is meaningful in 'direction' rather than 'return'. If January rises, the probability of the annual return rising reaches 80%."
PART 02
Why Does It Rise in January? (Or Why Not?)
단순히 '1월'이라서 오르는 것이 아닙니다. 수급의 역학이 숨어있습니다.
Mechanism Diagram
Step 1: December
Tax Avoidance Sell-off
Individual selling to avoid capital gains tax
Step 2: Transition
Low Price Re-entry
Burgain hunting when prices drop
January Effect
Traditional January Rebound
December Rally
Pre-emptive buying due to learning effect
The core mechanism is the re-entry of supply that avoided the major shareholder capital gains tax in December. However, this pattern has recently been pulling forward to late December.
Market Comparison
Avg Return
KOSPI Win Rate
58%
KOSDAQ Win Rate
54%
The January Effect is clearer in KOSDAQ (Small Cap), which has a higher proportion of retail investors, than in KOSPI (Large Cap). (Avg 2.7% Rise)
Strategic Implication
"The January Effect is a league for 'KOSDAQ/Small Caps', not 'KOSPI'. Large caps are more influenced by Earnings Season."
PART 03
Jan 2026 Investment Strategy: How to Gaining Statistical Edge
막연한 기대감 대신, 데이터에 기반한 카운터 펀치를 날릴 때입니다.
Action Plan Gantt
Nov-Dec
Tax-loss Harvest
Pre-load Small Caps (Oversold Small Caps)
Jan 1-10
Monitor Flow
Monitor KOSDAQ Flow (Target Supply Void)
Jan 15+
Shift Strategy
Shift to Earnings Surprise (Large Caps)
Feb
Risk Management
Prepare for Lunar New Year (Manage Risks)
Contrarian strategy: Buy when others sell in Dec, sell when others buy in Jan.
Risk Check
Earnings ShockHigh
Strategic Response: Check Pre-guidance
FOMC Rate DecisionMedium
Strategic Response: Macro Hedging
Every strategy has risks. Check the list.
Verdict
"The 'January Effect' exists but is not 'guaranteed'. Targeting the supply void in KOSDAQ small caps is the winning formula indicated by data."