Trader gem selling bonus

The Trader bonus is used to increase the coin gained from when the Trader personally sells gems or skins, whether singly or in open/closed/tied pouches/bundles. This bonus is based upon a Trader's Charisma, Trading, and Appraisal skill.

Overview

When a Player Character attempts to sell a gem or skin to an NPC buyer, the base appraisal value seen with Appraisal is the starting base value of the item. This is then modified by the player's Trading bonus. Non-Traders have a 0% Trading bonus. Traders have an inherent bonus that raises their base setting higher than 0%.

This is then further modified by +/- 10% in discrete 1% increments (accurate to at least 2 decimal places, such as 122.00xxxx%), easily confirmable with single gems/hides, or tied gem pouches.

For example, presume a hypothetical tied gem pouch worth precisely 100,000 kronar (10 plat kronar) when appraised certainly and exactly. When a non-Trader has an NPC gembuyer make an offer on it, they will see a range from 90-110% of the appraisal, that is, offers from 90000 to 110000 kronar, in increments of 1000 kronar (9 plat, 9.1 plat, etc., up to 11 plat).

According to the table of data below, a Trader with 60 Charisma, 394 Trading, and 331 Appraisal has a bonus of 40%, and a bonus of 50% when under the effects of Speculate Finesse bonus. This Trader, with the same pouch, would see offers ranging from 13 to 15 plat in 1000 kronar increments (30% to 50%). If that Trader uses Spec Finesse when selling, the offers can range from 14 plat to as high as 16 plat. (+/- 10% from a 50% base)

NPC buyers also subject a flat cap of 60% to selling. Anecdotal evidence appears that Traders with skill beyond this can hit the cap more often, but it is unknown how it works precisely.

Formula

The formula for the Trader bonus for selling is known to be a complicated function, the exact formula of which has not been determined.

What is known is that it is a piecewise function of some sort (that is, the formula changes across the range of variables), making it difficult to pin down a precise formula.

To that end though, a table follows containing data collected by the player of Naniaki over several years. Bolded values are where it is known that the Trader bonus rolled over to the next highest value at that exact stat/rank increase.

Date	Spec Finesse Bonus	Bonus	Circle	Charisma	Trading	Appraisal
		27	43	34	224	218
		28	43	34	224	219
		28	43	34	238	269
		29	43	34	238	271
		29	43	34	280	272
		29	43	34	296	273
		29	43	34	299	273
		30	43	34	300	273
		30	56	37	300	273
		31	56	38	300	273
		31	56	41	300	273
		32	56	42	300	273
		32	56	45	300	273
		33	56	46	300	273
		33	56	49	300	273
		34	56	50	300	273
		34	56	53	300	273
		35	56	54	300	273
		35	60	54	320	278
		36	60	55	320	278
		36	61	56	326	289
		37	61	57	326	289
		37	61	60	329	290
		38	61	60	329	291
		38	61	60	329	290
	45	38	61	60	332	293
	46	38	61	60	336	295
	46	38	63	60	347	308
	46	39	63	60	347	309
	46	39	63	60	350	312
	47	39	63	60	353	313
	47	39	67	60	369	323
02/21/11	48	40	67	60	371	325
03/08/11	49	40	70	60	384	328
03/24/11	50	40	71	60	394	331
05/12/11	50	41	75	60	418	345
06/24/11	50	42	78	60	436	365
07/05/11	50	43	79	60	443	373
07/14/11	50	43	79	60	447	378
07/26/11	50	43	80	60	450	386
11/23/11	50	45	84	60	482	414
12/30/11	50	47	90	60	520	434
01/26/12	50	47	90	60	535	445
02/10/12	50	48	90	60	540	448
02/20/12	50	48	90	60	548	453
03/10/12	50	48	95	60	555	455
03/31/12	50	49	96	60	568	459
04/15/12	50	50	98	60	581	483