Are there any methods/techniques that cover distributing cash into a specific percent of a portfolio asset class while gaining the best average price?
As a simple example, a portfolio starts with 100k cash. It eventually disburses its cash into four asset classes. This means 25k goes to purchase assets in each class. If one of these classes is the SP500 index, you might decide to divide the 25k into four purchases, getting a better price with each purchase. For example, assuming the SP500 is dropping, purchase might be made at:
$6250 buy 1350
$6250 buy 1325
$6250 buy 1300
$6250 buy 1275
For an average price of 1312.50 in your SP500 allocation of the portfolio. However, in the real world, you will not be so lucky. You might buy 1350, the SP500 drops to 1339, then bounces to 1362 and remains above 1350 for the next few weeks. You only made one purchase and was not able to take better advantage of gains in the SP500. Or, it may continue dropping to 1225. You spent all your 25% allocation for this class at 1275 and are not able to take advantage of a much better average price.
Funds are available upfront. Shorting isn't allowed.
What area covers techniques that deal with this topic?