MBS and Treasuries are both in distinctly stronger territory today after an overnight rally that reached it's zenith by 9am.  There are quite a few factors to credit for the strength.  In no particular order, these include:

• PIMCO/Gross correction.  It stands to reason that Friday's bond market losses were a bit sharper than they otherwise might have been had it not been a Friday.  Investors were trying to get ahead of the expected redemptions in the world's largest bond fund.  The only available headlines on the topic this morning indicate less redemption demand than initially forecast. 
• European Economic Data/ECB Frontrunning.  Econ data and inflation were generally soft overnight in Europe.  This didn't stoke any new rally demand, but kept the environment fertile for other factors.
• Democracy Protests in China have generally been credited with fueling a "risk-off" trade overnight (sell stocks, buy bonds).
• European periphery.  Remember Greece?  How about Spain?  These two countries were very much in the news in 2011-2012 during the Euro crisis and continue to experience aftershocks to this day.  No one is worried about an imminent systemic collapse of the Euro, but a lighter version of the same dynamic exists where the peripheral countries' debt sells off, thus benefiting core countries like Germany.  Greece has been in the news for wanting to exit its bailout plan early, and Spain for an independence vote in the Catalonia region.  Both bond markets got killed overnight, benefiting German and even US debt.
• Month/Quarter-end buying/flattening.  A "flattener" is a Treasury trade that favors the longer maturities vs shorter maturities.  For instance, you wouldn't even have to put any new money to work in Treasuries in order to benefit 10yr Notes.  You could simply sell an equal amount of 2yr notes to shift your duration preference (i.e. where you want/need the average maturity of your portfolio to be).  Flatteners are in fashion this morning, and the "long end" of the yield curve has more direct benefit to MBS.