A single consonant at the end of the infinitive form of the verb is doubled before -ed and -ing if the vowel just before that final consonant is spelled with a single letter and is stressed.
Thus, "cut," "cutting" ; "abet," "abetting." The final "t" of "market" and "bucket" is not doubled because the letter "e" before that word-final "t" is not stressed.
//Brits sometimes ignore this rule before -l, -m, and -p:
travelling; programmed; worshipped.//