Planet Fitness, a gym chain, on Monday started selling $800 million of bonds backed by most of the company’s assets, the latest in a string of recent deals known as whole business securitizations.

Guggenheim structured the deal and is helping sell the fixed-rate bonds, which comes in two portions of $400 million each. Both are rated BBB by S&P Global Ratings and Kroll Bond Rating Agency, according to people familiar with the matter. Proceeds will be used…