Investment Profit and Loss Calculation: How to Interpret Cost and Current Value?

When the current price of an investment is higher than the purchase price, it may appear to be a profit at first glance. However, for an accurate assessment, the number of shares, average cost, commissions, currency, cash inflows, and completed transactions must all be considered together. Calculating investment profit and loss is not merely a matter of comparing two prices; it involves determining the difference between the cost and the current value using a consistent method. This calculation reflects past performance, does not guarantee future returns, and does not, on its own, constitute a buy or sell decision.

What is cost basis?

Cost value refers to the total amount paid to acquire an asset. In the simplest case, it is calculated by multiplying the number of units by the unit purchase price:

Total cost = Quantity × Unit purchase price

If 100 shares were purchased at 40 TL each, the base cost is 4,000 TL. If transaction commissions and other direct expenses are to be included in the cost, these are added as well. Whichever method you choose, it is important to maintain the same approach to enable comparisons across periods.

The logic is the same for assets such as foreign currency, gold, or mutual funds. However, purchases made on different dates and at different prices create the need for an average cost calculation. Additionally, for assets denominated in foreign currency, both local price and exchange rate fluctuations can affect the total result.

How is average cost calculated?

When the same asset is purchased through multiple transactions, a simple price average does not yield accurate results. Transactions must be weighted according to the number of units. For example, suppose you purchased 10 units at 80 TL and 30 units at 100 TL:

• Cost of the first transaction: 10 × 80 TL = 800 TL
• Cost of the second transaction: 30 × 100 TL = 3,000 TL
• Total cost: 3,800 TL
• Total units: 40
• Weighted average cost: 3,800 TL ÷ 40 = 95 TL

The simple average of 80 TL and 100 TL would be 90 TL, which would yield a misleading result because three times as many units were purchased in the second transaction. If commissions are included, they are added to the net cost of each transaction, and the same calculation is repeated.

How is the current value calculated?

Current value is calculated by multiplying the quantity held by the price on the selected date:

Current value = Current quantity × Current unit price

If the current price of the 40 units in the example is 110 TL, the current value is 4,400 TL. Since the asset has not yet been sold, this amount represents the estimated market value displayed on the screen. In an actual sale, the final amount may differ due to the bid-ask spread, commissions, taxes, liquidity, and price movements.

Current value for physical assets

For physical assets such as homes, vehicles, or collectibles (excluding gold), there may not be a reliable and consistent market price. The value of these items is manually estimated by the user. Listing prices are not final sale prices. biriqim does not provide real-time real estate or vehicle valuations, nor does it conduct appraisals or title verifications; the physical asset values you record are solely for personal tracking purposes.

Unrealized gain or loss

If the asset is still in the portfolio, the difference between the cost and the current value is referred to as an unrealized gain or loss:

Unrealized gain/loss = Current value − Cost of the remaining position

In the example above, subtracting the cost of 3,800 TL from the current value of 4,400 TL results in an unrealized gain of 600 TL. The percentage change is approximately 15.8%, calculated by dividing 600 TL by 3,800 TL. If the price were 85 TL, the current value would be 3,400 TL, and the unrealized loss would be 400 TL.

The term “unrealized” is important because the result is not finalized until the asset is sold. This figure changes as the current price fluctuates. Additionally, the positive difference shown on the screen may not be the same as the net amount received after taxes and transaction costs.

What is a realized gain or loss?

When all or part of the asset is sold, the result for the relevant amount is considered realized. The simplified formula is as follows:

Realized gain/loss = Net sales revenue − Cost of the quantity sold

If 15 out of 40 units are sold at 110 TL, the gross sales revenue is 1,650 TL. Using the weighted average cost method, the cost of the 15 units sold is 15 × 95 TL, or 1,425 TL. The realized difference, excluding expenses, is 225 TL. The cost of the remaining 25 units is tracked as 2,375 TL.

Tax cost methods and reporting rules may vary depending on the country, asset type, and individual circumstances. You should not use the calculations on your personal dashboard in place of an official tax return; consult a qualified professional when necessary.

Why aren’t deposits and returns the same?

Adding 10,000 TL to the portfolio increases its total value; however, this increase is not investment return. Similarly, withdrawing funds from the portfolio does not, by itself, mean a loss. In a sound analysis, the following movements are distinguished:

• New deposits and withdrawals
• Buy and sell transactions
• Dividends, interest, and other cash inflows
• Commissions, taxes, and custody fees
• Changes in value due to market prices or exchange rates

Without this distinction, strong savings habits may appear to be the result of high investment performance. However, it is more informative to see separately how much of the portfolio’s growth comes from returns and how much comes from price movements.

The impact of exchange rates on foreign currency investments

While the price of a stock denominated in dollars may rise by 5 percent, the USD/TL exchange rate may fall. In this scenario, the investment may show a positive change in dollar terms but a lower or negative change in TL terms. The opposite is also possible. Therefore, reviewing the cost in both the transaction currency and the selected base currency helps interpret the result more accurately.

The type of exchange rate used for conversion and the date are also important. Buy, sell, and reference rates may differ. The TL equivalent shown on the tracking screen is an approximate valuation; the actual conversion amount may vary due to the financial institution’s spread and fees.

Profit and Loss Screen Reading Checklist

1. Verify that the amounts and transaction records are complete.
2. Check whether commissions are included in the cost.
3. Distinguish between realized and unrealized results.
4. Do not interpret new cash inflows as returns.
5. Evaluate price movements and exchange rate effects together for foreign assets.
6. Read the percentage change in value alongside the portfolio weight.

biriqim helps you compare your current value by organizing the asset amounts and cost information you enter. It is solely a tracking and analysis tool; it does not execute transfers, does not perform transactions on your behalf, and does not guarantee any investment results.

Frequently Asked Questions

How is percentage profit calculated?

In the simple approach, the profit or loss amount is divided by the cost value and multiplied by 100. More detailed performance methods may be required if there are cash flows, dividends, or transactions on different dates.

Should commissions be added to the cost?

It is helpful to factor in direct transaction costs to see the net result. The key is to apply the chosen method consistently across all transactions and not to confuse it with official tax calculations.

Does an increase in current value mean I should sell?

No. The current value merely reflects the estimated market value at the selected point in time. A buy-or-sell decision requires an assessment of your goals, risk tolerance, time horizon, and personal circumstances.

Track both cost and current value

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Disclaimer: This content is for general informational purposes only; it is not investment, trading, tax, or accounting advice.