Billionaire Mark Zuckerberg has a high-class problem.

With virtually all of his net worth tied up in Facebook’s slumping stock price, his wealth, at least on paper, is roughly half what it was when Facebook first went public.

The hoodie-wearing Harvard grad is worth only about $10.2 billion, according to the Bloomberg Billionaire’s Index.

While that sum is equal to the yearly gross domestic product of the Bahamas, it’s a humbling amount for the 28-year-old tech whiz, who is no longer counted in the top 10 richest list.

When Facebook went public in May at $38 a share, Zuckerberg’s fortune topped $20 billion. Since then, however, his stake has continued to plunge in value, with the stock falling below the $20 level yesterday. It closed at $19.87.

Zuckerberg will continue to sweat the stock price so long as he is chained to his shares, which he can’t start unloading until a lockup expires on Nov. 13.