MM
Worth 6 points before any premium square, and the 10th highest-scoring of 96 — tied with 1 other.
MM extends into 2 three-letter words, which is the 7th least extendable of 96 — tied with 2 others. That is the number worth memorising: a two-letter word is a place to put tiles, but a well-hooked one is a place to put them where the board stays open.
Every hook
- H→HMM
- U→UMM
No letter after MM makes a word.
Not all of them are equally reachable, which a bare count of 2 hides. MM hooks on 2 distinct letters, and the ones you are likeliest to be holding are U (26% of opening racks) and H (14% of opening racks). The rarest is H, at 14%.
How often you can actually play it
Out of an opening rack, 0.42% of the time you hold the letters for MM outright, the least likely of the 96. Counting a blank as whichever letter is missing lifts that to 2.38%, though spending one of the two blanks on a two-letter word is rarely the play. Exact hypergeometrics over the 100-tile bag, not a simulation.