There is still a risk, even if small, that for whatever reason, the deal doesn't go through, yet hanging on for a couple per cent might not warrant that 'exposure'. Of course, the opposite holds, in that another (higher) offer could also come along, so it's a trade-off to consider.
Additionally, and probably just as important, you're talking about a circa 3 month timeline before you would receive payment for the transaction, assuming it does go ahead. If one takes their profits now, they forgo a couple per cent or so, but they are able to immediately redeploy those funds into other investments in an effort to outperform the small gains left on the table. In essence, it comes down to opportunity cost.
