[1]

=INDEX(A2:A100,MATCH(MAX(B2:B100),B2:B100,0))

appears a tad faster than

[2]

=LOOKUP(2,1/(B2:B100=MAX(B2:B100)),A2:A100)

which is a tad faster than

[3]

=LOOKUP(2,SEARCH(MAX(B2:B100),B2:B100),A2:A100)

The difference can probably be attributed to the fact that [1] operates
on range objects, while [2] and [3] must process calculated arrays.

Krishnakumar wrote:
Hi,

This avoids the division, but don't know how much efficient it is,

=LOOKUP(2,SEARCH(MAX(B2:B100),B2:B100),A2:A100)

HTH