PHATsakk43
Last Authlim of the True Lord of Tyranny
It is written in the core books somewhere, but I can’t remember where it is. It may be clarified in a Sage Advice post or in Tome of Magic or Book or Artifacts as well. 
However, in the example of individual initiative options on pg 95 in the PHB, Rath rolls a 2, has modified weapon speed of 0 due to a +4 axe and -2 due to haste and has initiative 0. So, zero via modifiers is definitely RAW.
I’ve always ran a modified roll of 0 as the fastest, except explicit stated effects where “X goes first” or “X goes last”.
				
			However, in the example of individual initiative options on pg 95 in the PHB, Rath rolls a 2, has modified weapon speed of 0 due to a +4 axe and -2 due to haste and has initiative 0. So, zero via modifiers is definitely RAW.
I’ve always ran a modified roll of 0 as the fastest, except explicit stated effects where “X goes first” or “X goes last”.
 
				 
 
		 and generally I couldn't care less about others' opinions (including Gygax's).
 and generally I couldn't care less about others' opinions (including Gygax's). 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		