The electric carmaker's shares fell 9.3% to $220 when the stock closed on Thursday after the quarterly report showed the company's net income dropping almost 1.8 times in the past quarter.
Musk's net worth dwindled by 7% to $210 billion, which was still not enough to dislodge him from the top spot in the ranking of the world's richest people.
French luxury goods tycoon Bernard Arnault, who heads mega-corporation Moet Hennessy Louis Vuitton (LVMH), is in the second place with $155 billion, narrowly followed by Amazon founder Jeff Bezos with $144 billion.