The claim is directly supported by x post 2045904379824255435, which states both key elements: a $172.2 billion weekly outflow from money market funds and that it was the largest on record, with the four-week moving average of withdrawals declining. However, no primary source such as an official industry release, regulator dataset, or fund flow report was found and validated in this run. The other supplied materials, ETF Tracker and x post 2046231401846968519, are unrelated. Because the only supporting evidence here is a secondary social-media post, the claim cannot be fully verified to a high standard.