Myself and my group weren't keen on the PF system after using it for 5 or 6 sessions so we've come up with a slight variant on it, bellow are the rules and an example of them in action. We've only just started using them so i cant say if they work any better or worse than the PF system in the long run but they seem cool so far. (replace the phrase profit factor for profit rating or PR)

Diminishing Profit
- Any Acquisition roll lowers the RT’s profit rating by an amount equal to its negative modifier/10. An acquisition roll always lowers the Profit Rating by at least one unless the modifier for the acquisition check is positive.
- Gains to PR are repeated on a regular basis (e.g. monthly)
- If an Acquisition roll fails an amount of PR equal to the number failed by can be burned in order to succeed.
- If the RT’s Profit rating at the end of an endeavour has dropped 20% (this number is still being worked out) of its starting number then all possessions with a –modifier must be maintenance tested.
- Items that fail a maintenance roll can be saved by sacrificing a number of items with a combined acquisition modifier of the failed item +10

A Rouge Trader starts with a profit rating of 40 and decides he wants to buy himself and each of his 3 command crew a best quality power weapon. These rolls are all at -20 (very rare, negligible, best craftsmanship) so if they can be located the RT’s profit rating goes down by 8…ouch. Instead the RT cuts a deal and combines the purchase of these weapons as a -30 roll only loosing 3 profit rating (4 separate tests would cost a lot more than 1 slightly more difficult test for buying in quantity).

Having dropped down to 37 PR the trader decides its time to get some more cash in the coffers. He decides on a military endeavour to liberate (and claim ownership) of a mining operation that has been overrun by Eldar Pirates. In order to successfully combat these pirates the RT decides to acquire some soldiers and upgrade his ship with a military hanger. To prepare the RT travels to a system which contains both a hive world and a forge moon specialising in munitions. The RT decides to hire a company (100) of crack troops with average quality training, thanks to the sheer press of humanity on the hive world these troops are easier to find than usual (Average +10) and the scale + craftsmanship provide no additional modifiers. With some fortune the deal is made and the RT’s profit factor diminishes by another -1 (minimum). Finally with a PR of 36 he heads to the forge moon to have average quality military hangers installed. The Hangers are war tech so have an automatic -30. they are a little more common at this location than normal so have Average availability (+10) and the common craftsmanship has no further modifier. The RT makes a further roll at -20…tricky. The roll fails by two and as the RT really really wants those hangers he burns another 2 PR to make the deal, loosing a total of 4PR (PR 32!). The RT’s finances are at critical stage (he has lost 20% of the PR the group started the endeavour with) if he does not make good in this endeavour he will likely have to sell or store some of his gear.

After a hard fought battle the RT wins the mining operation. The basic PR gain from the operation is 4PR, in addition the ships barracks and military hangers each add 1 (they are military components that add +1 PR if an endeavour has a military theme) from the initial endeavour for a total of 6PR gain. The mining op also brings in a further 4 PR each month provided the RT can ship the minerals, as the RT does not have that ability he needs to contract out to a transport captain who will take a 1PR cut from each shipment. The RT will now gain a further 3PR per month and has a final PR of 38 (enough to avoid those maintenance rolls!), not quite as well off as he started but now with a lucrative business under his control and a few good men to get him more.

Eager to get right back out there and earn more profit the RT heads right onto a new endeavour, he intends to investigate a rumoured warp passage to a lost Squat fortress world. If he can locate and chart the passage he will have a very nice opportunity to set up a trade agreement and a very profitable agreement of passage to offer. Its unfortunate that his military additions wont render extra PR this time but oh well.
To get started he needs to spend a small fortune on a rare old chart (-1PR, PR37), and buckles to the pressure of the command crew wanting to purchase some more exotic items, thankfully (for the RT) only 1 of the 4 items can be located. The good quality Heavy Bolter with suspensors demanded by his arch militant sets his PR back a further -1 (PR 36)
After some time exploring the rumoured area the RT locates a derelict waystation. He boards and discovers a xenos infestation! Those troops will be useful after all. Establishing a military strongpoint the RT leads his command crew into the station on a raid to destroy the nest and succeeds. Reactivating the old cogitators they discover that this is an old imperial waystation guarding the entry to the warp passage. If the RT wants to invest in getting the waystation fully operational he will control and be able to tax the passage. Because the RT is feeling particularly wary of spending more at this time he decides that he wants to get everything but the weapons operational using the existing systems (poor quality) this amounts to a -10 check which even using a little fortune the RT fails by 3, once again he throws caution to the wind and takes a -4PR to succeed (PR 32) however this gets the Waystation operational and he can gain a monthly increase of 2 PR from this exploration endeavour with a one off bonus of +1 PR due to his trophy room which now has some weird Xenos hanging in it (PR 35). All of this work carries on to the end of the month and the RT receives a further +3 from his mining operation (PR 38).

The RT persuades his crew simply to make do with some luxuries while he gets a compartmentalised cargo hold fitted (-1PR, PR37). Eager to make the most out of the barely exploited warp passage he heads back to the waystation and through to the long forgotten squat fortress world. There he discovers to his dismay that the most likely looking fortress is besieged by Xenos. Taking a risk the RT bombards the area around the fortress gates from orbit devastating the Xenos, he then leads his troops and command staff down before the enemy can regroup. Although they are heavily outnumbered after a mighty onslaught of the Xenos the squats open their fortress doors and assist the RT in driving back the rest. Grateful to see other sentients for the first time in generations the squat lord agrees to a lucrative trade deal with the RT and furthermore offers even greater reward if the RT can use his ship to make a definitive strike against the Xenos’s subterrainian queen. The RT agrees the trade deal (+4 PR, +1 for Cargo bay = PR42) and promises to return with more troops soon in order to destroy the queens nest. The RT then returns to his ship and back to main port where he spends some shore leave awaiting income (+5 PR, PR47) and recruits and equips more men to destroy the Xenos Queen. Though he will have to loose some more PR to recruit and equip more soldiers things are looking on the up, and the RT now has a regular income of +8 PR, +10 if he manages to get some ships to transport goods rather than contract out.

Before the RT can make the arrangements to swell his ranks of troops in order to help the Squats he is approached by a broker interested in making immediate use of the military capabilities of him and his vessel for a one off endeavour. The broker is willing to pay a vast amount of money for a defended research lab to be cleared out of its current occupants without extensive damage to the facility. For this he is willing to offer the vast wealth of 10PR. The RT considers that this is an ideal job for his small but capable force of men. Before setting off the RT decides to try and equip his troops with good craftsmanship carapace and hellguns (both -20 rolls) he fails on both rolls and it seems the stations main weapon merchant isn’t willing to part with those kind of numbers without a long credit checking process the RT can’t wait for. As he only failed the carapace roll by 5 and he stands to make good money from the mission he burns a massive 7 PR to get it done.
Finally just before he leaves he enquires about a Transport vessel that has been recently impounded at the station, it turns out that he can get a very good deal on it if he buys it now, he successfully bids and gains the void going vessel for 3 PR.
Having strained his finances to breaking he sets off to do the mission and claim his bounty. Arriving at the labs he deploys his crack troops leads his command staff into the fray, everyone has strict orders to take great care not to damage the facility. All is going very well, the carapace the RT bought makes losses to his troops minimal and his own efforts take his command staff to the central core with little effort. It seems a lab worker is trying something nefarious so the RT’s psyker attempts to quickly and cleanly destroy the mans mind but disaster strikes! The warp becomes unstable and instead of the telepathic attack a terrifying demon appears. Before the demon can be banished it runs amok and critically damages the core. The RT and his assets barely make it back aboard ship before the whole facility goes into meltdown… needless to say the RT will not be getting his pay. Unfortunately this turn of events means that the RT will not be able to cover the credit notes he has been liberally distributing in the last few days and he now needs to carefully examine his assets to see where he can cut costs or reclaim thrones in the short term. The RT makes an acquisition roll for every item he or his staff have that have a negative modifier. As a result the RT has to shut down his military hangers, cancel the purchase of replacement plates for the good quality carapace (lowering its quality to average) and sell off 3 of the 4 best quality power swords… dark days indeed. But the RT cannot bring himself to part with his family heirloom power sword and decides to instead re-jig his finances and chooses to close down the military portion of his hanger bay (returning it to a standard hanger bay) sell of the arch-militants heavy bolter and his good quality digi-flamer (the combined acquisition modifier for the military hanger bay, the heavy bolter and the digi flamer is 10 more than that of a single best quality power sword, so he can re-prioritise what is sold off or shut down.)

I don't know this sound more like Rogue Accountant than Rogue Trader. The existing rules are nice as they allow quick resolution.

So far, I think it adds alittle more believabllity to the system. I was already agonizing over how not to let the game turn into "Monty Halls Lets Make a Deal". THis would allow me to al the very least force the Rogue Trader to look at his check book and possible have to make decisions based on his financial climate. I will try to get some feedback on how this works.!

I was working on an system to control how often a RT gets to make acquisition test. I want it to be reasonable, while letting the player build up his reserves to make a number of purchases at once (for instance, refitting a wreck by buying all the needed components at once). I settled on a token system. It seems robust, although we will see how it works in play. The basics of the system work as follows:
Each month the RT gets a number of tokens equal to his PF. I use coins, as it makes keeping track of the tokens a lot easier. He must pay 1 token per major asset (starship, regiment of troops, or base) that is not dedicated to making a profit (off-screen as it were) per month. The RT can spend tokens to make acquisition tests as follows:
25 tokens is a normal acquisition test
10 tokens is an acquisition test at -10
5 tokens is an acquisition test at -20
1 token is an acquisition test at -30, or any test the RT would automatically succeed at with full PF

The idea behind the system is that the RT can concentrate his wealth on a few items or spread it out trying to find deals and maybe getting nothing. As the RT becomes more powerful, his resources will not only make tests easier, but his house will be able to field more purchases per month. I plan on certain other tests and situations requiring tokens. Repairing the ship and replacing significant amounts of crew will probably be 1 token per test. The tokens will be stored by me in between game sessions in a Ziploc. I hope that it will give the players an actual feel of their financial means without becoming to cumbersome.

"- Gains to PR are repeated on a regular basis (e.g. monthly)"

I tried this in my game, and it failed! my players just said, lets travel a lot to skip time or just waited for the profit, and they didnt want to go anywhere, because they got there money anyways, why make stupid deals and adventures if you get money anyways from your old deals?

It is an innovative way to limit acquisition rolls. The 2 main problems I see are it could promote players sitting around waiting for for their money to pile up. Also it assumes the modifier to the acquisition roll is equal to the cost.. not so.. which do you think costs more a common drive system for your cruiser -10 or -1 PF, or a single best quality boltgun, which has a -20 to the roll or -2PF?

The way I do it is take the players PF and give them 1 roll for every 10 points (or fraction thereof) for large scale acquisitions, and double that in small scale acquisitions per time period (usually a month but this is variable based on the stories need). Small scale is equal to about a couple hundred thousand thrones or less, large is anything over that. Or for a real world example say anything under a million US dollars is small scale. As a note this is how many rolls they get not successful rolls. It takes time to do all the searching (or have their minions do it) for items and do the negotiating, successful or not.

So for example a group with 53 PF would get 6 large and 12 small scale acquisition rolls per month. I also find it useful for situations where it is not worth the time to do out all the rolls. For instance they want to buy a gift/bribe for the station master, unless they wish to drag it out, perhaps doing research on his likes and whatnot to get the perfect gift for him, I just say ok it costs you a small scale acquisition and move on.

Since people seem to think it's an issue.

I'm putting together a similar system where there is a consumable "Profit Factor" with periodic gains, and the way I felt I could prevent players from just sitting around is by creating events much like Misfortunes. Instead of letting players sit back and relax, throw an Ork Kaptin at their profit source and force them to respond or else lose it. They'll get the message that whether they sit around or not, you're going to make them go on an adventure. Better that they increase their rate of gain instead of fight to protect what they have.

Ultimately, as a GM, you're the most important factor in balancing the game and preventing obvious exploits.