Alrighty, here we go. Feel free to use this until something official gets published. I get paid for this stuff now (Professional writer, YAY!), but, this is short and it's my birthday, and tradition is that you should ALWAYS give something away on your birthday, so...
Wak's Totally Unofficial Scrip Conversion Rates
MegaCorporation Rate (Scrip to Nuyen)
Saeder-Krup 4:5
NeoNET 10:11
Shiawase 1:1
MCT 101:100
Wuxing 3:1
Ares 35:10
Evo 33:1
Renraku 80:1
Horizon 100:1
Aztechnology 750:1
Saeder-Krupp is the biggest Megacorporation of them all, being an industrial giant, yes, but a financial giant even moreso. That their scrip is more valuable than Nuyen is yet another source of the famous SK Swagger.
NeoNET is the only other corporation whose scrip is more valuable than the Nuyen at this moment, but it's notoriously volatile, stretching from as much as 2 more or 10 down, depending on current Matrix technology.
Shiawase is the Gold Standard. The first Megacorp demanded that it's currency be pegged to the Nuyen and this rule has remained in effect ever since. The legendary stability of the risk-adverse corporation has long made it the financial reserve currency of choice. Shiawase can be depended on.
That MCT's currency has never been allowed to be more valuable than stodgy old Shiawase's is a constant source of minor irritation to them. Fuchi was more valuable, but since they went down, no Asian company has ever scratched the vaunted 1:1 rate. This is made more painful by the true corporate side wanting to pass them, but the Yakuza behind the board refusing to risk the stability of Shiawase.
Wuxing is a financial corporation, though one far shy of Sader-Krupp, and keeps a reliable rate as well. Indeed, it's said that their accountants are quite particular at keeping the 3-to-1 ratio as a sign of good fortune and good luck.
Ares has a rate between that of the UCAS and the CAS, its two major sources of income. As their economies move, so does Ares'.
Evo's rate took a dire plunge when their headquarters left Japan. Officially, it was because they were headquartered in Russia and it was assumed that a rate closer to the Ruble would be appropriate. Everyone knows that this was actuallythe Japancorps taking a measure of revenge against their wayward cousin for 'betraying' the nation.
Renraku has recovered from the perils of old, but has a long way yet to go.
Horizon's products are intellectual property, not physical assets, and this continues to impact their currency's value. Information and public opnion just change so fast...
Aztechnology comes in last, always kept low by the other Megas and now in a risky war that's shaken investor confidence, such as it was. They've lost 20% in the past year, so that war needs to end soon.
(Edit: Found the old rate wasn't 100:1 on Pesos, but 500:1, so, I changed the chart.)