Provides two methods for calculating the cost price
1. Diluted cost price
Formula: Diluted cost price = (Total purchase amount during the holding period - Total sale amount during the holding period) ÷ Quantity held
Meaning: Refers to the breakeven price during the holding period of a certain stock (excluding commissions and fees). Users can achieve a balanced profit and loss when selling at this value. It considers the profit and loss of each transaction during the holding period (excluding cash dividends, rights issues, etc. for now). It takes into account both buying and selling changes. The profit and loss corresponding to the sale of stocks will raise or lower the cost price, and it may even result in a negative cost price.
2. Average cost price
Formula: Average cost price = (Average cost price before purchase × Quantity + Price of this purchase × Quantity) ÷ Quantity held after purchase
Meaning: Refers to the average cost of the current holding of a certain stock (excluding commissions and fees). It only considers buying and does not consider the changes from selling. The profit and loss corresponding to the sale of stocks do not dilute the cost price, but convert to realized profit and loss.
Example 1: Establishing position
If the customer did not hold #BTC☀️ before day T, then on day T bought 1 btc for 100000 dollars
Diluted cost price = (Total purchase amount during the holding period - Total sale amount during the holding period) ÷ Quantity held
= (100000*1 - 0) ÷ 1
= 100000
Average cost price = (Average cost price before purchase × Quantity + Price of this purchase × Quantity) ÷ Quantity held after purchase
= (0 + 100000*1) ÷ 1
= 1000000
If the stock price closes at 105000 that day, compare the position under the two methods:
Example 2: Reducing position, continuing example 1
If the customer sells 0.5 btc at 110000, then
Diluted cost price = (Total purchase amount during the holding period - Total sale amount during the holding period) ÷ Quantity held
= (100000*1 - 110000*0.5) ÷ 0.5
= 90000
Average cost price = remains unchanged when buying btc = 100000, but the profit and loss from selling part = (110000 - 100000) × 0.5 = 5000 counts towards realized profit and loss
Example 3: Increasing position, continuing example 2
If the customer buys 0.5 btc again for 105000 dollars
Diluted cost price = (Total purchase amount during the holding period - Total sale amount during the holding period) ÷ Quantity held
= (100000*1 + 105000*0.5 - 110000*0.5) ÷ 1
= 97500
Average cost price = (Average cost price before purchase × Quantity + Price of this purchase × Quantity) ÷ Quantity held after purchase
= (100000*1+110000*0.5) ÷ 1.5
= 103333.333...