Vanity Fair has an excellent story (well worth reading in its entirety) by Milton Esterow, founder of ArtNews magazine, about the mess Picasso left behind with his enormous body of work, many heirs and no will. Here Esterow describes the size of the problem:

When Picasso died, 43 years ago at the age of 91, he left an astounding number of works—more than 45,000 in all. (“We’d have to rent the Empire State Building to house all the works,” Claude Picasso said when the inventory was completed.) There were 1,885 paintings, 1,228 sculptures, 7,089 drawings, 30,000 prints, 150 sketchbooks, and 3,222 ceramic works. There were vast numbers of illustrated books, copperplates, and tapestries. And then there were the two châteaux and three other homes. (Picasso lived in and worked in about 20 places from 1900 to 1973.) According to one person familiar with the estate, there was $4.5 million in cash and $1.3 million in gold. There were also stocks and bonds, the value of which was never made public. In 1980 the Picasso estate was appraised at $250 million, but experts have said the true value was actually in the billions.

Picasso did not leave a will. The division of his holdings took six years, with often bitter negotiations among the heirs. (There were seven then.) The settlement cost $30 million and produced what has been described as a saga worthy of Balzac. The family, writer Deborah Trustman noted at the time, “resembles one of Picasso’s Cubist constructions—wives, mistresses, legitimate and illegitimate children (his youngest born 28 years after his oldest), and grandchildren—all strung on an axis like the backbone of a figure with unmatched parts.”

Eventually, Claude Picasso was put in charge of the Picasso Administration which, Esterow details, has substantial income but limited infrastructure:

For all its efforts, though, the Administration, which now employs a staff of eight people, gets mixed reviews in the art world. Critics complain that responses to authentication requests are slow, that neither Claude Picasso nor the other heirs are scholars, and that they have not created an advisory committee or made any plans to publish a catalogue raisonné. “It’s a pity that one of the world’s greatest artists doesn’t have a team of experts doing this research,” one dealer told me. Claude, for his part, points out that he has been immersed in Picasso since birth. “The heirs have decided not to publish for the time being a catalogue raisonné as objects surface still which were not catalogued,” he wrote in an e-mail. Regarding authentication, he said, “the requests are very often not professionally formulated. On the average 900 requests are filed yearly. Verifications of the information provided sometimes can be labor-intensive. Artworks need often to be examined in the flesh.”

The Battle for Picasso’s Multi-Billion-Dollar Empire  (Vanity Fair)