How to Get Email Newsletter Subscribers

I run a financial newsletter, in a specific financial niche, and I'm looking to grow as fast as possible. I worked in email marketing so I recognize that you can't just buy and cold-email 100,000 addresses, however I'd love some advice on the best way to grow quickly.

- Is it by buying an email list but then emailing them from another domain to opt in?
- Is there someone here that might be in the financial niche that would be open to cross promoting?

I'm looking to gain 20,000 subscribers with a 45% open rate in the next month or so

Ask current subscribers to forward yours newsletters to their friends and also so many.... Put the subscription box on every page of your website, promote your newsletters at seminars and talks..

@BigAllenEnergy - did you get anywhere with this?
20k newsletter list would translate to around 20k USD/month, or almost half a mil per year.
If its in the financial niche, it would be around double that at least, depending on what soft of people you would have there.
Very lucrative.

I have a few newsletters and always open to hear new ways of acquiring subscribers

@BigAllenEnergy how's your financial newsletter doing now?