I've accepted a new job and given my required month's notice to my current employer, both are startups. My employer asked me if I could stay a little longer, as they're going through an investment round, and I'm the only expert in my particular area and so they'll need me to stay or find a replacement before due diligence starts.
I asked my new employer if they would be happy for me to start later than a month, but they're not for understandable reasons. I'm to help them achieve an upcoming deadline, and I obviously agreed to a start date on accepting the job. I've informed my current employer, but they're pushing me hard to try and re-negotiate with my new employer.
My current CEO is someone I've known a long time, and I don't want to make things difficult for them, but I also don't want to make a bad impression with my new employer. I didn't deliberately time my departure badly, but my current employer keeps investment plans and our financial runway very close to their chest, and therefore we never really know what position the company is in.
Has anyone else ever been in this situation, and what advice can you give?
Clarrification Clarifying a couple of things, due to feedback on my question. I have a months notice, as this is what is required by my contract of employment. This is normal in the UK, where I’m based. It’s possible for a company to require several months notice, if they include it in your contract.
I don’t want to work two jobs at once, as I’ve young kids.
Update Just an update for those of you who are curious. I told my current employer I will not be extending my notice period. They have now asked to be put in contact with my new future employer, to negotiate my leaving/start date with them directly. I have of course said no, as it seems to me to be completely unprofessional to even ask me this. I now feel I'm in a fight to stop them actively trying to sabotage the relationship with my future employer, for their own perceived short term gain.