Portfolio Allocation Calculator (VND)
If you live and work in Vietnam, your investable savings probably sit across a few buckets denominated in Vietnamese dong: equities or local fund certificates, bonds, physical gold (a long-standing store of value here), and cash. Asset allocation is the decision of how much weight each bucket gets — and it drives your portfolio's risk and volatility far more than picking the right individual security.
This calculator takes your total portfolio value and a target weight for each class, then computes the target VND amount per class. Enter what you currently hold in each bucket and it produces the rebalancing trades: how much to buy or sell in each class to bring the portfolio back to plan. One rule is enforced: the target weights must sum to 100% — otherwise the allocation is undefined.
Why rebalance at all? Over time the classes grow at different rates, so the actual weights drift from your targets. In the worked example below, a 500.000.000 VND portfolio targeting 50% stocks has drifted to 64% stocks (+14 percentage points) after an equity run-up — meaning it now carries more risk than you signed up for. Rebalancing forces you to trim what has risen and add to what has lagged — a disciplined "sell high, buy low" that emotion usually resists.
A caveat for everything here: the target weights and current holdings in the examples are illustrative inputs to demonstrate the method, not a recommended portfolio. The right mix depends on your age, goals, risk tolerance and personal circumstances — including any home-country tax and reporting obligations on overseas investments, which this tool does not model.
How the calculator computes the plan
Step 1 — Target amount per class
For each asset class:
Target amount = Total portfolio × Target weight (%)
| Symbol | Meaning |
|---|---|
| Total portfolio | The amount you are allocating (e.g. 500.000.000 VND) |
| Target weight | The percentage you want in that class (all classes sum to 100%) |
| Target amount | Total × weight — the VND you should hold in that class |
Constraint: the four target weights must sum to 100%. Entering 50 + 20 + 15 + 15 = 100% is valid; any other total should be corrected before reading the results.
Step 2 — Rebalancing trades
Compare each target against what you currently hold:
Trade = Target amount − Current holding
- A positive result means buy that much to reach the target.
- A negative result means sell that much because you are overweight.
Because the total does not change, the buys equal the sells: rebalancing is moving money between classes, with no fresh capital required unless you choose to add it.
The "age in bonds" rule of thumb (illustrative only)
A classic heuristic sets your bond percentage roughly equal to your age, with the rest in equities. A 35-year-old → about 35% bonds, 65% stocks; on a 500.000.000 VND portfolio that is 175.000.000 VND of bonds and 325.000.000 VND of stocks. Treat it as a conversation starter, not a formula — many long-horizon investors use "110 − age" or "120 − age" for the equity slice to tilt toward growth. Adjust for your own goals and risk tolerance.
What the model leaves out
It ignores transaction fees, bid–ask spreads, and any taxes triggered when you sell — costs that can make over-frequent rebalancing uneconomic. It also forecasts no returns for any class. The output is an allocation plan, not a promise of performance.
Worked example: 500.000.000 VND portfolio, 50/20/15/15 target mix
Illustrative assumptions: a 500.000.000 VND total; target weights of 50% stocks, 20% bonds, 15% gold, 15% cash (summing to 100%). After an equity run-up, the actual portfolio has drifted from target, shown in the "Current" column.
| Asset class | Current | Target | Rebalancing action |
|---|---|---|---|
| Stocks | 320.000.000 | 250.000.000 | Sell 70.000.000 |
| Bonds | 80.000.000 | 100.000.000 | Buy 20.000.000 |
| Gold | 60.000.000 | 75.000.000 | Buy 15.000.000 |
| Cash | 40.000.000 | 75.000.000 | Buy 35.000.000 |
| Total | 500.000.000 | 500.000.000 | turnover 140.000.000 |
Reading the table: stocks now make up 64% of the portfolio — overweight versus the 50% target by +14 percentage points — so you sell 70.000.000 VND of stocks to bring them back to 250.000.000 VND. The proceeds fund the buys: 20.000.000 VND of bonds, 15.000.000 VND of gold and 35.000.000 VND of cash — exactly the amount sold, so no new money is needed.
Total turnover to rebalance is 140.000.000 VND (28% of the portfolio in this example). Because every trade carries fees and may trigger tax, many investors rebalance only on a schedule (every 6–12 months) or when a class drifts past a preset threshold (say ±5 percentage points), rather than constantly. Enter your own holdings to see the exact buy/sell amounts for your portfolio.
Frequently asked questions
What is portfolio asset allocation?
Asset allocation is how you divide your total capital across asset classes — stocks, bonds, gold, cash — using preset target weights. Illustrative example: a 500.000.000 VND portfolio targeting 50% stocks, 20% bonds, 15% gold and 15% cash means 250.000.000 VND in stocks, 100.000.000 VND in bonds, 75.000.000 VND in gold and 75.000.000 VND in cash. This weighting decision drives portfolio risk far more than picking individual securities.
How do I calculate rebalancing trades?
Rebalancing brings a drifted portfolio back to its target weights. The formula is Trade = Target amount − Current holding: positive means buy, negative means sell. In the 500.000.000 VND example, stocks are at 320.000.000 against a 250.000.000 target → sell 70.000.000 VND; the proceeds buy 20.000.000 VND of bonds, 15.000.000 VND of gold and 35.000.000 VND of cash. Buys equal sells, so no new capital is required.
Do the target weights have to add up to 100%?
Yes. The target weights across all classes must sum to 100%, or the target amounts will not reconcile with the total and the plan is undefined. For example 50 + 20 + 15 + 15 = 100% is valid. The calculator flags any total other than 100% so you can fix it before reading the rebalancing trades.
How often should I rebalance my portfolio?
There is no single right interval. Two common approaches: calendar-based (e.g. every 6–12 months) or threshold-based (only when a class drifts more than ±5 percentage points from target). Because each trade carries fees and may trigger tax — turnover reaches 140.000.000 VND in the example — rebalancing too frequently can be uneconomic. Picking a simple rule and sticking to it matters more than timing the market.
What is the "age in bonds" rule of thumb?
It is a quick heuristic: set your bond percentage roughly equal to your age, with the rest in equities. A 35-year-old → about 35% bonds and 65% stocks; on 500.000.000 VND that is 175.000.000 VND of bonds and 325.000.000 VND of stocks. It is illustrative only, not a standard — many investors use "110 − age" or "120 − age" for the equity slice to tilt toward growth. Adjust for your own goals and risk tolerance.
Why does my portfolio drift away from its target weights?
Because the classes grow at different rates. When stocks rally, their share balloons: in the example the target is 50% but the actual weight has climbed to 64% (+14 percentage points), leaving the portfolio riskier than intended. Rebalancing returns the weights to target and, as a byproduct, forces you to take profits in what has risen and add to what has lagged.
Should gold and cash be part of my allocation?
They can be, if they are part of your plan. In Vietnam, gold has long been a popular store of value, while cash (including short-term deposits) provides a liquidity buffer and dampens volatility. In the example, gold at 15% is 75.000.000 VND and cash at 15% is 75.000.000 VND. You can set any weights as long as they sum to 100%; the calculator computes the target amount and buy/sell trade for each class.