Blog › How to Manage Your Average Cost in a KOSPI Rally — Split Purchase Strategy
Have you been hearing a lot of stock talk lately? As of May 2026, KOSPI has surpassed 7,300 points, setting new all-time highs day after day. Individual investors are increasingly pulling funds from crypto and big tech to enter the domestic stock market. But the more dramatic the rally, the deeper the question: "When should I buy?"
The record highs are exciting, but there's also that nagging fear of "What if I'm buying at the top?" The key to reducing that anxiety while not missing profit opportunities is average cost (average purchase price) management. Today, we'll fully break down the split purchase strategy for managing your average cost in a rally — with real-world examples.
In the first half of 2026, KOSPI has been on a powerful upward rally, driven by the government's corporate value-up program and foreign capital inflows. Securities firms are even forecasting KOSPI could reach up to 10,000 points by year-end.
In such a rapidly rising market, 1–2% daily swings have become normal. With the index at such elevated levels, even small percentage moves feel like dozens of points. Geopolitical tensions since March have made 3–4% single-day swings routine.
In this volatile environment, going all-in at once can lead to significant losses if your timing is even slightly off. In contrast, using a split purchase strategy turns volatility from a risk into an opportunity to lower your average cost. The more the market fluctuates, the more advantageous the environment becomes for investors who buy in tranches.
Average cost is the average price per share you paid when buying a stock multiple times at different prices. It's the total amount invested divided by the total number of shares held.
Lowering your average cost means you reach break-even faster when the price recovers, and your return rate naturally improves. Even in a rising market, split purchases mean earlier lots were bought at lower prices, keeping your overall average cost below the current market price.
However, calculating your average cost manually every time you buy is surprisingly tedious — especially with multiple stocks and many transactions. That's where an average cost calculator becomes invaluable (see the CTA card below!).
So how should you actually split your purchases for maximum effect? Depending on your situation and temperament, there are three main approaches.
In a rally, ③ Staged Entry is particularly useful. For example, if you want to invest ₩3M in Samsung Electronics, buy ₩1M now and set limit orders for the remaining ₩2M at −5% and −10% from your first purchase price. If prices rise, your initial ₩1M gains; if there's a correction, you add at lower prices, reducing your average cost.
The biggest thing to avoid in a rally is chasing momentum blindly. When stocks hit new highs every day, FOMO peaks and you want to jump in without thinking. But if you invest your entire budget at the top and a correction follows, it's psychologically very hard to hold on. Always avoid investing based on themes or rumors without proper company analysis.
Split purchasing and averaging down aren't unconditionally good. There are a few important traps to be aware of.
First, don't add to a stock indefinitely as it falls. If a company's earnings are deteriorating or its business model is broken, continuously adding to "lower your average cost" will only snowball your losses. Averaging down only works on quality stocks that are genuinely expected to recover.
Second, split purchasing without a plan becomes a poison. Buying and selling on emotion with no defined rules for frequency or amount leads to confused average cost tracking and a chaotic portfolio. Set clear rules upfront: "I'll invest X% of my total capital in Y tranches."
Third, relentless averaging down can drain your liquidity. If you keep buying every time the price drops, you may have no cash left when a better opportunity arises. Always keep 20–30% of your investment funds in cash — it's a good habit.
In the end, investors who survive longest are the ones who capture the best opportunities. In a market like 2026's — where uncertainty and sharp rallies coexist — building a steady investment structure matters far more than short-term returns. Split purchasing and average cost management are the most fundamental and powerful tools for that structure.