The explosions in Boston are horrific and will go down as another sad day in this country's history.
However, staring at CMBS loans all day leads my thoughts immediately to potential exposure. It is probably a little too soon, but nonetheless there are likely to be lasting consequences to the impacted area.
The two primary explosions that caused the most damage were in the 600 and 700 blocks of Boylston Street (specifically the addresses listed were 671 and 755). The only CMBS property in the immediate vicinity is the 761- 793 Boylston Street loan in CGCMT 2007-C6, representing 0.24% of the deal. In the horrific photos, which are widely available elsewhere, you'll notice a line of stores behind the aftermath starting with a Crate & Barrel on the left side (West) of the images, and continuing right (East) you'll see an Atlantic Fish Co, Forum (the blast appeared to be centered here), and Starbucks. The building with the Crate & Barrel and all the buildings to the left (West) of it back to Fairfield Street are part of this collateral property.
Only three other loans have properties within a few blocks, and both are approximately 1-3 blocks away from the attacks:
GSMS 2007-EOP - 500 Boylston (JV) (I don't *think* this has been released)
CGCMT 2007-C6 - The Wesleyan Building (0.20% of deal)
JPMCC 2007-LD11 - 399 Boylston (1.45% of deal)
Each of these are office and less likely to be impacted then street level retail.