I ran for elected office in Colorado. I refused to take donations because I didn't want to go through the paperwork and regulatory hassle of taking donations. H

I ran for elected office in Colorado. I refused to take donations because I didn't want to go through the paperwork and regulatory hassle of taking donations. However, every penny I spent on my campaign still had to be reported to the state. Funding the campaign by yourself still needs to fill out paperwork only in months you actually spend money instead of every month (with legal restrictions on what you are allowed/required to do with any funds left over after the election). Bloomberg ran because if Sanders' tax plans would have cost Bloomberg about $2 billion in higher taxes, so spending 1/4 of that to keep Sanders from getting the nomination was a reasonable maneuver.