Hello, earlier this year I withdrew all funds from my Roth account (principal and earnings). I'm going into a business venture now, and would like to know if there is a way to characterize this Roth withdrawal as a conversion into a 401k with my upcoming company formation. Is this possible, or is it too late? Thanks in advance.
Technically, it is too late. The IRS, however, does not actually receive any information on WHEN, within a year, you withdrew/contributed funds. They will receive a 1099 (showing distribution) and a 5498 (showing contribution), but that will be for the year. I would advise you to not undo what has already been done, as it is beyond the rules. as LRD mentioned, all "rollovers" are suppose to be completed within 60 days, although the IRS can only really truly figure this out with an audit. You would also have to reinstate your IRA first (by a "rollover") and then rollover into your 401k plan.
To clear up one thing LRD said, only one IRA to IRA rollover is allowed per year. This is not to be confused with rollovers from 401k to IRA, IRA to 401k, as those are not subject to the one rollover per year rules.
Also, your new 401k would need to accept 2 things: 1) funds from outside the plan and 2) roth funds. I wouldn't say it is extremely rare to find this, but it isn't common either. Since you probably have some influence on the shaping of the plan, you may be able to do this. But, I am skeptical of being able to pull together a plan in the next couple of weeks if not already put together, but I don't have a lot of experience doing that either.