Twitter CEO Dick Costolo and two of its co-founders, Evan Williams and Jack Dorsey, collectively lost $900 million, according to a Wealth-X estimate, after the San Francisco-based micro-blogging company released on Wednesday its first earnings report since it went public in November last year.
Investors saw weak growth in the number of active users on Twitter, pushing the value of its shares down by as much as 17% in after-hours trading.
The microblogging site had an average of 241 million monthly active users as of 31 December,
2013, up 30% year over year, and an average of 184 million mobile users in the fourth quarter of 2013, an increase of 37%.
But the growth of the user base has slowed, with Twitter adding only 9 million users in the final quarter of 2013.
Below are Wealth‐Xs estimates of the personal fortunes of Costolo, Dorsey and Williams at and after market close on 5 February, 2014:
* Dick Costolo
Net worth at market close: $590 million
Net worth after market close: $480 million
* Jack Dorsey
Net worth at market close: $2.7 billion
Net worth after market close: $2.5 billion
* Evan Williams:
Net worth at market close: $3.4 billion
Net worth after market close: $2.8 billion
These estimates of the net worth of Costolo, Williams and Dorsey have been calculated after accounting for their shares in public and private companies, residential and passion investments such as art, planes and real estate, and is based on the most recent publicly available disclosure of their shares and options in Twitter.