David Wallis, head of funding at Nationwide, explained that as the institution typically had low funding needs and was an infrequent issuer (this is its third public RMBS in three years), he was confident of a positive reaction for Silverstone 2011-1.And to give investors as broad an opportunity as possible to access the programme, roadshows were scheduled for the week of October 3 in the US and Europe showing three and five-year bonds. The issuer was already aware, it seems, of which investors would express the most interest.”There was an expectation we would meet with strong demand in US dollars,” said Wallis.The dollar buyers did not disappoint. An initial update showed demand exceeding US$2.5bn for the three-year while the five-year sterling tranche lagged behind at £150m. The bonds were talked in line with Holmes - launched by Santander UK last month - at 155bp and 165bp area, and emerged at US$2.7bn and Â£150m in size at talk.The cost of issuing in euros, meanwhile, remains prohibitive - so much so that Nationwide avoided euro bonds completely. Wallis explained that the basis swap between euro and sterling was around 40bp, or just above, depending on the maturity.”It was difficult to justify issuing in euros for the economics of the transaction with the basis swap at that level,” Wallis said. On Friday, the three-year swap was quoted at 37bp/43bp.The size of the dollar tranche clearly compensated for the lack of euro notes though - as well as limited sterling bonds - while an usual fixed-rate dollar piece was added late on in the process. “We had interest from investors for a long-dated tranche and looked at a number of maturities. Nine years hit the right spot,” said Wallis.This tranche pays 4.15% until 2020, and then reverts to floating.RBS, meanwhile, pre-placed its deal entirely. Arran 2011-2, as with Silverstone, contained minimal sterling issuance, with investors seemingly preferring the liquidity of dollars. Printing on Monday, Arran was sold almost exclusively to JP Morgan and Citigroup (or affiliates of these two). Its structure included just Â£220m of sterling bonds, ?220m of euro notes and US$1.895bn in US dollars.JP Morgan bought the majority of the US$725m one-year Class A1c at three-month Libor plus 135bp and some of the 2.8-year Â£70m and ?220m Classes A2a and A2b at 160bp and 155bp respectively. Citigroup, meanwhile, also took some of the Class A2 bonds, and most of the Â£150m and US$500m 4.6-year Classes A3a and A3c at spreads of 175bp. STRUCTURAL VARIATIONS These levels are 5bp wider than Silverstone and Holmes for the three-year dollar notes and 10bp outside for the five-year bonds. Arran, however, typically trades back of Holmes and one source involved in the deal said it was down to it offering a standalone issue versus a master trust structure.Portfolio features may have also been an influence as Arran pool’s was just three months seasoned, included some buy-to-let as well as product switches. This resulted in credit enhancement of 22.4%, higher than both Holmes 2011-3 (16%) and Silverstone 2011-1 (17.2%).The demarcation between standalone and master trust has much larger pricing implications for the very short tranches with average lives of around a year or so. Hard bullets from master trusts aimed at US money market funds under Rule 2a7, for example, price more than 100bp inside amortising bonds in standalone issues.One source away from the deals explained that master trust structures such as those used by Santander (Fosse and Holmes) and Lloyds this year (Arkle) can factor in short-dated hard bullets because of the larger number of mortgages in a trust than in a single deal.There is more more cash flowing from the mortgage pool to assure investors of payment by a certain date. Typical pass-through deals would depend on the payment (CPR) rate, he said, and so do not have that guarantee. The downside is that bullets are more collateral-consumptive.Recent 2a7 notes have been priced in the low teens over Libor with maturities of a year or less. Standalone deals cannot match this, and even though the tranches at the top of the structure have short weighted average lives, the legal final maturities are considerably longer.Arran 2011-1, for example, had a one-year average life on its US$725m Class A1c, but a legal final maturity of 2048 - far too long for money market funds - which accounts for the 122bp pricing differential between this piece at 13bp and the 0.8-year tranche of Holmes.SIZE ACHIEVABLE IN DOLLARS What Holmes, Arran and now Silverstone 2011-1 do all have in common is highlighting that the US dollar market remains the only place to get deals done in size. These three have sold US$8.395bn of dollar bonds - that equates to a hefty 85% of the issues - compared with just Â£555m in sterling and only ?420m in euros.And it may not only be UK issuers that are coveting the US investor base, as sources suggest that Dutch issuers are also eyeing the market. It may not necessarily be in US dollar-denominated bonds, but funded in euros should they obtain 144a issuance capability. Doing so would allow them to target a large investor base that is clearly hungry for the spread offered by European products.It may require some explanation of the near 100% LTVs, or higher in some cases, that characterise Dutch RMBS, but from an investment point it can provide a substantial pick up from an asset class that has performed extremely well throughout the crisis.One European investor even estimated that a US buyer could make up to 50bp investing in a five-year or shorter euro-denominated Dutch RMBS paying around 155bp and swapping it to dollars.