If I had to guess, I'd say the top two accounts withdrawing funds are connected to @steemit2. @cdec84 received 350k STEEM from @steemit2 2 days ago. @eeqj used funds from @fdcb934e6cce which received 60k STEEM from @steemit3 2 months ago (and funds from @steemit2 before that). It could also be contractors being paid by Steemit, inc in STEEM.
top 4 withdrawing are steemit inc
no chance they are paid contractors, if they were they would be the highest paid in the world
also it is clear who controls this account and the others who sent transfers
@eeqj received 653K Steem indirectly from steemit inc accounts
@alpha is another received 10mill steem directly from steemit2