Seems to me that you hire an accountant for tax questions. Unless this cap gain is more involved than it seems, I don't know what he would really do for you. If the cap gain is short term, he might have some idea on how to stretch it into a long term gain. Otherwise, unless you have questions about how to invest tax efficiently with the proceeds, I think you just pay your tax and move on.
As far as DCA vs invest immediately, you will get different opinions on it here, for sure. Upfront I'll state that I believe in AA as opposed to market timing, so I say don't DCA.
My opinion is that you manage risk by having an appropriate asset allocation, and you want to get to what you decide your AA is right away. If you keep a lot of money in the bank while DCA'ing, your portfolio is severely underweighted in stocks, and you are at risk of missing a run-up. The market could be rising while you are trickling money in over time, and the day you put the last money in, the market could tank. Unless you have some strong feel about the market direction (and are willing to market time), there is no greater chance that the market will tank the month after you invest the whole lot vs. a year later after you complete the DCA.
I've heard the arguments for DCA. As far as I can see, it's an emotional decision. You fear making a major decision to invest the whole amount at once and have it immediately tank.
Let's look at it this way. I have $1M in the market right now. You just got your big lump and if you were to follow your AA plan you would invest $1M now, but you are also considering DCA'ing 10% every quarter (or at whatever pace you choose).
The market doesn't care at all where each of us came from with that $1M. If it's a good idea for me to keep my $1m in the market, it should be a good idea for you to invest it all now. Conversely, if it's a good idea for you to invest just $100K now,shouldn't it be a good idea for me to sell $900K (let's assume I'm even right now so there are no tax consequences) so I'm in the same position? After all, we share the same risk of losing money in a market downturn. The only difference is that one of us would be making an active decision, while the other is being passive, and the active decision is emotional. Most people find it tougher to accept the consequences of having a decision backfire, than the do accepting a missed opportunity by doing nothing.
In the end it's your money and you need to do what feels right to you and lets you sleep at night. Don't invest it all right away because RunningBum says to. But realize if you DCA, you are in reality a market timer rather than following an AA plan--and that's ok. If you don't see it that way, at least realize it is an emotional rather than a logical decision. I don't feel you should make emotional decisions about money, but if that helps you sleep better, go ahead.
