How does media know about celebrities net worth?

I see Amrita Roa has net worth of 20 million dollar, Ileana D' Cruz has net worth of 14 million dollar and Amisha Patel has net worth of 30 million dollar but these actresses barely gave any hit movies and they were never top actresses. On the other side, I see that Kat has net worth of 10 million dollar and she is much bigger star than those actresses. So how does media estimate the net worth of celebrities? Does the media take a guess or does the celebrities show their property?

No they don't. Nor do forbes. All these lists are bs. Famous supermodel Gisele bundchrn said forbes makes estimate on their own. No-one knows where celebrities invested. It is all bs. N if someone poses for these lists, that is called famous PR

Ileana was no.1 south indian heroine at one point until she moved to hindi. She must have earned alot. Then Kajal became no.1