Hello, I am writing this post to help our friends who are beginning to invest have a better idea of returns and the math behind dollar cost averaging.
Dollar cost average(-ing), DCA for short, is the action of buying a certain product, be it equities, gold, funds etc. over a period. This is similar to the common saying of "drop more, buy more!" or spreading your capital over a typical poker game. However, mentioning to buy when it drops is easy, but how much are you actually prepared to lose or/and do you have the next buying point ready?
Gut feeling aside, this post is to simplify the maths of DCA and newer investors such as me can learn how to appropriate their funds prior to making their first order. There are many reasons why one would buy a stock, maybe the market has fallen quite an amount from it's peak, friend's recommendation, rumors, analysis shown great potential, etc. this plan will only help once you have decided to start buying - it doesn't teaches you when to enter or exit.
Please take note that the price will definitely drop lower in a bear market at the end of your planned DCA. If you have done your research prior to purchase, further drops in prices shouldn't bother you much as you should be confident that the company will go strong and have good prospects that price falls are temporary. If not don't even start to buy, much less a DCA plan. You might also not be able to complete the plan due to price not reaching levels as low as planned but that should be expected while planning.
Ok lets move on!
Scenario 1. You have $10,000 cash you decide to invest in a certain company having a initial share price, p, of $10. Since the economy is unstable right now you decide to DCA, here is one way you can do it.
- 10k capital
- 3 splits
- 5% drop
The total amount invested at the end (of the 3rd purchase) is $8,550. Your paper losses at the end is $450. These are the only 2 values we will be concerned about right now, lets disregard the unused cash balance.
When share prices rises back to the price at which you first bought it, you will have a profit of $450, or 5.26% of invested capital. This 5.26% profit WILL always apply as long as you follow the 3 splits - 5% drop plan, be it the first purchase is worth $50k, $200k or $1 million.
Having said that, let the first purchase amount be x. By following the plan, your purchase will go by 1x, 0.95x, 0.9x = 2.85x
In order to ensure sufficient funds, your available capital must be 2.85 times more than your first purchase. So factoring in the minimum purchase of 100 lots and etc. you can do the calculations yourself.
Here are a few values to note.
Loss after 1st purchase = 0%
Loss after 2nd purchase = 2.56%*
Loss after 3rd purchase = 5.26% (of invested capital)
Any further losses isn't of concern since you are not buying any more.
*This is also your profit % after share price returns to p should your 3rd purchase threshold isn't hit.
Assuming you completed your plan, the price it needs to rise to to break even your costs is (total losses/total shares owned) + last bought share price. This scenario is pretty bad to demonstrate due to the fractions and all but you get the point.
Scenario 2. Will be going a little faster and more simplified now.
- 4 splits
- 5% drop
Your available capital must be at least 3.7 times of your first purchase cost.
When share price returns to p, your profits will be 0.05x+0.1x+0.15x = 0.3x. That gives us 0.3x/3.7x, or 8.11% of invested capital.
Loss after 1st purchase = 0%
Loss after 2nd purchase = 2.56%
Loss after 3rd purchase = 5.26%
(total)Loss after 4th purchase = 8.11%
Putting some numbers in.
1st purchase = 10x300 = $3,000
2nd purchase = 9.5x300 = $2,850
3rd purchase = 9x300 = $2,700
4th purchase = 8.5x300 = $2,550
Total = $11,100
To break even, (900/1200) + 8.5 = $9.25 (8.82% rise)
Scenario 3. This is slightly more drastic but still realistic.
- 3 splits
- 10% drop
Total cost = x + 0.9x + 0.8x = 2.7x
Your available capital must be at least 2.7 times of your first purchase cost.
When share price reaches p, profit is 0.3/2.7 or 11.1% of invested capital.
Total losses at the end of last purchase = (1x - 0.9x) + (1x - 0.8x) = 0.3x
0.3x/2.7x = 11.11% (of invested capital).
These are just 3 of the infinite possible DCA plans you can come up with, with it being even more complex should additional factors be added in such as : different amount of shares each purchase, perpetual/long term DCA, DCA over bear and bull market and many more.
I also didn't provide examples for scenarios of averaging up because it doesn't really make sense nor I have any benchmarks to relate. Firstly, one should really stop buying shares when it reaches ridiculous highs, DCA or not. Secondly, if I use original price p as reference, then DCA upwards will only result in losses, losing money isn't really the goal of investments isn't it.
If you are planning on having a perpetual DCA, you should also consider the price ceiling in which you stop buying anymore, save them up for a crash - the profits/effort ratio here is totally worth it.
That's all folks, thanks for reading!