Latest date for sending LOCI?

I have my letters of interest ready for now but I also have a couple of potential awards and activities coming out by April 28th. Should I send my Letters now or later?

It depends upon the college in question and what date they are releasing decisions.

Most of them I believe respond in up to 4 days and some can be uploaded immediately. They are all May 1st schools

I would send them now. Colleges are already calling students off of waitlists, and they are no doubt reviewing who they will call when they need to. You can say in your LOCI that you are hopeful of being awarded something, and specify what it is.

If the school is calling people now, don’t wait. But fwiw, my kid didn’t send any until the 28th and got into the schools the first week of may.

If the awards improve your application and offset something that might have been a concern, it could be worth waiting. If they merely show more of the same (an English prize when you have all As and some published /awarded work), maybe not worth waiting.