Progressive Summing in Column

[quibilty]

How do I create a formula that accomplishes the following:

IF column a value is >-500 to appear in column b, but
ONCE column a value is <-500 to get that value to continually be displayed in column b?

Essentially, is there a formula that STOPS COUNTING once a value of <-500 is reached?


-------a----------b
1-----"0"---------"0"
2-----"0"---------"0"
3-----"0"---------"0"
4----"94"--------"94"
5----"94"--------"94"
6---"-206"-----"-206"
7---"-206"-----"-206"
8---"-206"-----"-206"
9---"-136"-----"-136"
10--"-510"-----"-510"
11--"-881"-----"-510"
12--"-881"-----"-510"
13--"-725"-----"-510"
14--"-425"-----"-510"
15--"-110"-----"-510"

[benishiryo]

hi quibilty. assuming it starts in A2, try:
=IFERROR(INDEX(A$2:A2,MATCH(TRUE,INDEX(A$2:A2<-500,),0)),A2)

[quibilty]

Works great! Thank you.