I will just ask my bank upon transferring large amount from Coinbase to buy a house. For sure, I do not qualify for a mortgage. I live in the US and Coinbase is base in San Francisco, CA. Therefore, I am sure Coinbase will certainly send my withdraw reports to the IRS, and I just need to file my tax.  I do not think my bank will have a problem with me withdrawing my funds that is base in the US soil, but I just need to show my bank and file my tax to the IRS how I got the funds in my Coinbase bitcoin wallet in the first place.