Kent Green was a racehorse that raced at Longacres in Seattle for several years. In 1989 the league was paid $200 by an owner who was slightly behind on his league-fees. On the same day, Second Commissioner For Life Jack Fleming was going down to watch (and wager on) the Longacres Mile. The owner who was tardy with league fees gave Mr. Fleming $20 to put ("$10 to win and $10 to place") on a horse named Kent Green. The SLUBA Bosses at the regular Sunday morning meeting then discussed whether to put the $200 on Kent Green in a like manner rather than putting it in the league treasury. Eventually the SLUBA Bosses decided to keep the money in the treasury.
Of course, Kent Green came through to easily win the race. The team owner received about $120 for his $20 investment and the SLUBA Bosses thought about the possible $1,200 that the league treasury missed by not sending the additional money to the track...
Ever since, the league treasury has been known as the "Kent Green".