Alesco is quick, with a two-day mean and one-day median on its 2024 filing. Speed isn't the issue.
Thoroughness is. Of the 326,818 deletion requests it reported for 2024, 255,015 were complied with in full, 63,779 were complied with only in part and 8,024 were denied. Around one in five wasn't fully honoured, and only two of the 41 registrants reporting 100,000 or more deletion requests did worse. The same filing counts 580,584 requests to opt out of sale, the thing this form does, with 12,644 denied. A newer table on Alesco's own privacy policy, which it labels as its registration effective July 1, 2026, puts sale opt-outs at 30,219 received and 12,416 denied. Treat a partial outcome as a realistic possibility rather than an edge case.
Practically, that means keeping evidence. Note the date, screenshot the submitted form, and keep the deletion email in your sent folder. If marketing mail continues months later, you have something concrete to point at when you write again, and the filed contact for the company is legal@alescodata.com.
One thing you can't do is verify by searching, since none of this is published. The only signals available are Alesco's own responses and, eventually, the post.