MFS Moderate Allocation Fund (Prospectus Summary): | MFS Moderate Allocation Fund

MFS® Moderate Allocation Fund

SUPPLEMENT TO PROSPECTUS

The date of this supplement is August 26, 2011.

MFS®Asset Allocation Funds

MFS® Conservative Allocation Fund,

MFS® Moderate Allocation Fund,

MFS® Growth Allocation Fund, and

MFS® Aggressive Growth Allocation Fund

Effective immediately, the following replaces the second paragraph of the sub-section entitled "Principal Investment Strategies" beneath the main heading "Summary of Key Information" for MFS Moderate Allocation Fund:  

As of August 26, 2011, the fund’s target allocation among asset classes and the underlying funds was:

Bond Funds:	40%
MFS Emerging Markets Debt Fund	3%
MFS Global Bond Fund	5%
MFS Government Securities Fund	10%
MFS High Income Fund	5%
MFS Inflation-Adjusted Bond Fund	5%
MFS Research Bond Fund	12%
Specialty Funds:	6%
MFS Absolute Return Fund	1%
MFS Commodity Strategy Fund	3%
MFS Global Real Estate Fund	2%
International Stock Funds:	13%
MFS International Growth Fund	3%
MFS International New Discovery Fund	1%
MFS International Value Fund	3%
MFS Research International Fund	6%
U.S. Stock Funds:	41%
MFS Growth Fund	8%
MFS Mid Cap Growth Fund	7%
MFS Mid Cap Value Fund	7%
MFS New Discovery Fund	1.5%
MFS New Discovery Value Fund	1.5%
MFS Research Fund	8%
MFS Value Fund	8%