Generate response to the question/instruction based on a piece of given material

Question/Instruction: Can you summarize the key details of Credit Suisse's CSMC Trust 2015-WIN1 offering, including the size, rating, and composition?

Given material: Credit Suisse (CS) is set to bring the year’s second prime, jumbo residential mortgage-backed securitization to market. The $381.59 million offering was assigned mostly AAA ratings by credit ratings agency DBRS.
The offering, CSMC Trust 2015-WIN1, is backed by 525 loans with a total principal balance of $381,595,526. The underlying loans have an average balance of $726,849, larger than the average loan size in the year’s first jumbo RMBS from Two Harbors Investment Corp (TWO), which carries an average loan balance of $688,392.
The loans in CSMC Trust 2015-WIN1 carry a weighted average FICO score of 766, a weighted average collateralized loan-to-value ratio of 71.4%, and a weighted average debt-to-income ratio of 33.2%.
According to DBRS’ presale report, the underlying borrowers also carry clean payment histories.
According to DBRS’ report, 100% of the loans are fixed-rate, first-lien mortgages and none of the loans carry interest-only features. A composition like that poses the lowest default risk, given the stability in monthly payments, DBRS said.
Also of note in the deal is that approximately 45.2% of the borrowers have more than one mortgaged property.
Additionally, the CSMC Trust 2015-WIN1 has a “relatively moderate” geographic composition, DBRS said. California represents nearly 50% (49.4%) of the underlying loans, and the top three states represent 59.4%, with Florida ranking second with 5.7% and Massachusetts ranking third with 4.3%.
The originators for the mortgage pool are New Penn Financial (20.2%), Quicken Loans (19.3%), Caliber Home Loans (7.6%) and various other originators, each comprising less than 5%.
The loans will be serviced by Select Portfolio Servicing (68.8%), New Penn doing business as Shellpoint Mortgage Servicing (20.2%), Fifth Third Mortgage Company (4.8%), PHH Mortgage Corporation (3.7%), First Republic Bank (1.5%) and EverBank (0.9%).
Click the image below to see DBRS’ presale ratings for the offering’s classes.
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