[zeckalpha]

With DCA you have the additional costs of keeping cash around. Unless you mean serial lump sum (investing when you get paid).

[nonethewiser]

That's typically why people DCA.

Besides, isnt the opportunity cost is completely independent of the return you're getting from the sp500?

[zeckalpha]

Serial lump sum is not quite DCA. Both involve a series of purchases.

The opportunity cost is the inverse of the S&P500 in that case.