The Swiss banks involved included Credit Suisse, Julius Baer and Basler Kantonalbank.
The transferred data is reported to "between 4 million and 6 million e-mails between Swiss bankers and their U.S. clients, including the names of those involved." Randall Jackson, Swiss Banks Turn Over Encrypted Data to U.S. Officials, 2012 TNT 21-6 (2/1/12).
This new Swiss gambit of complying but not complying is apparently an attempt to show good faith on their part. I doubt that compliance without compliance will be perceived by the U.S. as any form of good faith. In truth, it appears just a way to stall the process. If the U.S. was really serious about the 1/30/12 deadline, the deadline has now been passed without any semblance of good faith compliance. The ball is in the U.S. Court. I suspect the U.S. knows how to parry that thrust and thrust back (to mix the metaphors).
Oh, we might all shrug, this is just the Swiss being the Swiss. That is the point. (In an analogous context, we might just say "Oh, with a shrug, it is just the Somali pirates being Somali pirates," but we take measures when feasible to move them into compliance or make them suffer if they do not.)
Emma Thomason, Swiss banks hand over encrypted data in U.S. tax row (Reuters 1/31/12), here.
This is a short discussion about the Fifth Amendment issue of forcing a U.S. person to disclose the encryption key. In United States v. Fricosu, 2012 U.S. Dist. LEXIS 11083 (D. CO. 2012), here, an encrypted laptop was seized. The issue was whether owner of the laptop could be ordered to decrypt or produce the encryption key over her Fifth Amendment objection. The Court rejected her Fifth Amendment argument. The Volokh conspiracy blog has an excellent discussion of the issues that swirl around that Fifth Amendment claims. See Encryption and the Fifth Amendment Right Against Self-Incrimination (Volokh Conspiracy Blog 1/24/12), here. Of course, the Swiss banks do not have a Fifth Amendment claim. And probably the Swiss officials turning over the encrypted information or having access to the key are outside the U.S. compulsory jurisdiction.