Mark Ronson Says Justin Bieber's $200 Mil Catalog Sale Is Great Move

Mark Ronson says Justin Bieber's call to sell off his music catalog is a sweet decision, and he also says Bieb fans can chill ... this is not a sign the singer's ready to hang it up.

We got the producer/DJ Tuesday at LAX, and he doesn't see J.B.'s estimated $200 million catalog sale as a dead end -- noting it could be a good thing for fans, possibly showing Justin has a bunch more music to make, and is just looking to maximize profits off what he's done so far.

Obviously, Mark doesn't know exactly what's going through Justin's head ... but he notes money's got to be a big factor.

As we reported, Justin had his eyes on the big deal with Hipgnosis Songs Capital in December, which included his entire music catalog -- 6 albums over a decade, as well as all singles and collabs. Hipgnosis announced the closing of the mega sale Tuesday.