I've bought quite a lot of the dip during the tech selloff last few weeks but now I'm overweight in my allocation to certain sectors. Should I sell partially if and when the stock prices go up later?

There are 2 mindsets when it comes to portfolio allocation.

1. Those that pick an ideal allocation and immediately stick to that allocation. They manage their portfolio by constantly rebalancing

2. Different assets, markets, sectors take turn all the time. Late last year while tech and disruptive innovation was going up, cyclicals like financials were lagging severely. Right now we see a shift where financials, materials, industrials are booming while disruptive innovation are coming down. These cycles create opportunities at different point of time.

I personally prefer taking advantage where there is opportunity. What that means for you could be ... since you decided to add more to ARKK now, instead of selling it when it goes up a little, just add less in future. Instead add more to others when they are showing opportunities.