Le Clos won gold in the 100m butterfly on the final day to add to his two gold medals in the 50m and 200m butterfly events on Saturday.
Coming close to world records in all his races, he again just missed out in his last race.
“It was a good race and I did it strategically. I think I’ll only get better by the end of the year,” he said.
“I was confident today and I believe I can get a world record. Singapore has always been a good place to race for me.”
With a tally of 27 gold medals in the series, which took place over seven legs starting in Doha in August, it was the third time Le Clos had won the prestigious title with a purse of US100,000 (approx R1.1m)
Hosszu added two more gold medals to her tally, bringing her total to an unprecedented 51 golds in the series.
She also won six silver and nine bronze medals.