Right from the start of the overnight session, global bond markets were on the back foot.  During Asian hours, this was contained to a 3bp spike in 10yr yields that merely drifted higher for the first few hours.  Once Europe came online, things deteriorated quickly. Greek yields shot more than 100bps lower and German yields began their worst selling spree in more than 2 weeks. 

Until 10am, US Treasuries were still VERY much "along for the ride" (bringing MBS with them after 8am).  Then we saw some old fashioned cause and effect as stronger Existing Home Sales pushed yields higher.  In other words, strong data motivated selling in bond markets.  That's not always a given these days.  Heck, it may not even be more than a 50/50 chance any more.

Unfortunately, additional motivation for weakness meant that bond markets were in the snowball zone.  That's where momentum becomes its own reason for more momentum.  Traders who may have been betting on lower rates after 10yr yields hit 2.50 earlier this month would have certain "stop loss" levels in place.  That means they'd sell bonds in order to preserve as much of the gains as possible.  When they sell, it makes yields go higher still, which runs the risk of triggering more stop-losses. 

All told, 10's rose 10.4bps by the 3pm close.  Fannie 3.5 MBS fell a whopping 25/32nds, and most lenders repriced at least once.

MBS Pricing Snapshot
Pricing shown below is delayed, please note the timestamp at the bottom. Real time pricing is available via MBS Live.
FNMA 3.0
99-10 : -0-25
FNMA 3.5
102-27 : -0-20
FNMA 4.0
105-25 : -0-14
2 YR
0.6620 : +0.0410
10 YR
2.3740 : +0.1128
30 YR
3.1650 : +0.1163
Pricing as of 6/22/15 4:36PMEST

Today's Reprice Alerts and Updates
A recap of Alerts and Updates provided to MBS Live subscribers.
1:26PM  :  ALERT ISSUED: Negative Reprices Now Likely to be Widespread
10:16AM  :  ALERT ISSUED: Negative Reprice Risk Incrementally Increasing
10:03AM  :  ALERT ISSUED: Some Negative Reprice Risk for Early Lenders
9:01AM  :  Bond Markets Correcting Overdone Overnight Sell-Off

MBS Live Chat Highlights
A recap of featured comments from the Live Discussion on the MBS Live Dashboard.
Sung Kim  :  "heard the fed is rasing rates this year"
Matthew Graham  :  "Greece is definitely contributing to the move, but in the absence of Greece-related headlines it's hard to say if we wouldn't still be seeing a majority of today's weakness."
William Hansen  :  "If this is the swing in yields just because there could be a deal in place what will the swing be if the deal does happen? "
Andy Braun  :  "if you run it at 618 it will give you an ineligible for credit score but will indicate refer or approved (which will give you a hint if it will take it at 620) I think"
Ali Faraj  :  "borrower is at 618 now"
Ali Faraj  :  "have to wait for a credit supplement "
Ted Rood  :  "620 is the lowest, potentially, but you'd need really low LTV and great DTI for that to fly."
Ali Faraj  :  "what is the lowest FICO Fannie will accept for a cash out refi"
JEREMEY BECK  :  "TR - Yes on the 7/1"
Ted Rood  :  "Conventional 7/1 arms qualify at the initial interest rate, right?"
William Hansen  :  "It seems all we do is go 1 step forward and 2 steps back with these yields."