lished ▁in ▁ 2 0 0 0 , ▁by ▁a ▁mer ger ▁of ▁Gla x o ▁Well come ▁and ▁Smith K line ▁Be ech am , ▁G SK ▁was ▁the ▁world ' s ▁sixth ▁largest ▁ph arma ce ut ical ▁company ▁according ▁to ▁For bes ▁as ▁of ▁ 2 0 1 9 , ▁after ▁Pf izer , ▁Nov art is , ▁Ro che , ▁San of i , ▁and ▁Mer ck ▁& ▁Co . ▁G SK ▁is ▁the ▁t enth ▁largest ▁ph arma ce ut ical ▁company ▁and ▁# 2 9 6 ▁on ▁the ▁ 2 0 1 9 ▁Fort une ▁ 5 0 0 , ▁ranked ▁behind ▁other ▁ph arma ce ut ical ▁companies ▁including ▁China ▁Resources , ▁Johnson ▁& ▁Johnson , ▁Ro che , ▁Sin oph arm , ▁Pf izer , ▁Nov art is , ▁Bayer , ▁Mer ck , ▁and ▁San of i . ▁ ▁The ▁company ▁has ▁a ▁primary ▁listing ▁on ▁the ▁London ▁Stock ▁Exchange ▁and ▁is ▁a ▁constitu ent ▁of ▁the ▁F T SE ▁ 1 0 0 ▁Index . ▁, ▁it ▁had ▁a ▁market ▁capital isation ▁of ▁£ 8 1   b ill ion ▁( about ▁US $ 1 0 7   b ill ion ), ▁the ▁fourth ▁largest ▁on ▁the ▁London ▁Stock ▁Exchange . ▁It ▁has ▁a ▁secondary ▁listing ▁on ▁the ▁New ▁York ▁Stock ▁Exchange . ▁ ▁The ▁company ▁developed ▁the ▁first ▁mal aria ▁v acc ine , ▁R TS , S , ▁which ▁it ▁said ▁in ▁ 2 0 1 4 , ▁it ▁would ▁make