Determining a team's luxury tax number is not quite as simple as looking at their payroll and comparing it to the luxury tax threshold. This is about 98% of the job, of course, but there are a couple of other tweaks. For salary minutia fans like myself, who express our love for number crunching through this and games at 888poker.com, these tweaks are important. The following list of adjustments is quoted from Larry Coon's CBA FAQ, a page from which my entire career is sourced.
1) Cap holds and exceptions are ignored.
2) Any "unlikely bonuses" that were actually earned are added to the team salary.
3) Any "likely bonuses" that were not earned are subtracted from the team salary.
4) Any trade bonuses for players received in trade after the last regular season game are added to the team salary.
5) Any amounts from settlements of grievances are added to the team salary.
6) Players who signed as free agents (i.e., not draft picks) and make less than the two-year minimum salary are taxed at the minimum salary for a two-year veteran and not their actual salary.
For minimum salary players whose salary is partially paid by the league only the amount paid by the team (the two-year minimum salary) is taxed.
The salaries of players waived via the Amnesty provision are exempt from the luxury tax.
A team's luxury tax number is taken from the last day of the regular season, then adjusted for the above criteria. We of course aren't at the last day of the regular season yet, hence the title of this post, so points 2, 3 and 4 can be ignored for now. (Bonuses are adjusted with hindsight. For now, we can only work with what we know.) Point number 1 means removing the cap holds and unused exceptions that are charged to a team's cap - these are relevant in the calculation of a team's salary cap room, but not to its luxury tax situation. And point number 5 does not, I believe, apply to anybody currently.
This leaves point number 6, the bolded one, as the most relevant. Essentially, rookies and sophomores signed to the minimum salary, who weren't signed as draft picks but as free agents, are charged the third year player's minimum salary instead. The wording here is important - it matters not whether the player is with the team that drafted him or not, only what he signed as. For example, Robert Sacre was drafted by the Lakers, signed a one year minimum salary contract with them, then re-signed to a three year minimum salary contract, but even though he is now earning the $788,872 minimum salary with the team that drafted him, he nevertheless re-signed as a free agent, and thus counts for tax purposes as the third year minimum of $884,293. Additionally, Quincy Acy was drafted by Toronto, signed to a three year contract which paid the minimum in years two and three, and was recently traded to Sacramento. Yet even though he is now not with the team that drafted him, he signed as a draft pick, and thus counts only as the second year minimum against the Kings's tax number.
This applies also to players on prorated contracts. Therefore, despite being waived sufficiently early so as to not have his minimum salary prorate beyond the $100,000 he was already guaranteed (by clearing waivers on the 34th day of the season, Harris earned 34/170ths of his $490,180 rookie minimum contract, equal to $98,036), Elias Harris will nevertheless count against the Lakers's tax number as $176,859 (equal to 34/170ths of the third year minimum of $884,293). Also note that it applies to any contract paying below the two year veteran's minimum salary, so Dwight Buycks's $700,000 salary is not his $884,293 tax number.
With these things in mind, and with asterisks used to highlight players to whom point 6 applies, here is an examination of luxury tax situations league wide as things stand.