Credit Pulls when Investing

[Dane MacLeod]

I am just getting started and applied for my first pre-approval. I know that lenders hard pull when making a mortgage decision. However, I am going to want to start buying more properties. My question is when investors are flipping tens and hundreds of homes a year, are they using their personal credit when applying for loans and how do they maintain a high enough credit score when they have so many loans outstanding (credit pulls for each)? Thanks!