Typically multi-stage investors like A16Z would like to lead the follow up round from seed. Seed is just a way to get in to the company, and the next rounds are

Typically multi-stage investors like A16Z would like to lead the follow up round from seed. Seed is just a way to get in to the company, and the next rounds are where the actual money is for large funds. If the company is killing it, there is no reason for the VC not to invest. You basically want every single piece of the cap table you can without messing up the company. This is where the whole "signaling risk" issue came from. If you look up Crunchbase where A16Z are the lead investor and organize the list by company name, you see that it's more likely they have lead at least 2 rounds: Charthop (seed, A, B), Compound (seed, A), Clubhouse (A,B,C), Databricks (A,D,E,F), Descript (seed, A), Fivetran (B,C,D)... Founders can also prefer the previous investor because often you can get lower dilution, you already know the investors, no additional board seats and get the round done in one day vs multi week or month raise. Founders sometimes can also prefer choosing a new lead investor but I wouldn't say it's typical at all that everyone wants a new investor. Another multi-stage investors, Sequoia, WhatsApp raised all their rounds from Sequoia and no-one else. Sequoia also led Stripe's seed, Series A and have participated in every round so far. In the end it's the founder who chooses the lead investor.