IMO, A FEW THINGS RESPONSIBLE FOR THE WEAK SHARE PRICE PERFORMANCE.

(1) rising bond yields and the spectre of higher debt servicing costs impacting a number of REITS/INTEREST SENSITIVES.  that being said, 6.5% dividend yield still attractive, even with backdrop of higher yields.  Furthermore, very little debt is maturing in the next two years, and SIA has $235mm in liquidity and over $1 billion in unencumbered assets.  Weighted average cost of debt of 3.4% still quite attractive.  
(2) concerns over new LTC legislation in Ontario, although the increased hours of care will be funded by the government, and there will be new enforcement actions for poor operators.  
(3) INFLATION - wages, food, supplies, etc., for Sienna and others are rising.  How much can be passed thru in form of higher prices per bed (incurred by primarily the resident in retirement and predominantly the province in LTC)?  
(4) Pace at which occupancy can return to pre-pandemic levels.  For Sienna, LTC currently at 83.5% and Retirement at 80.6%.  As pandemic cost reimbursement starts to dwindle, key to get occupancy back up.  Demographic trends are positive for senior living, but at what pace do things normalize???
(5) Liquidity within smaller/mid cap Canadian equities in general has fallen over the past few months.  
(6) The longevity of this fourth wave and higher number of LTC outbreaks.  In Ontario, 19 LTC facilties currently face an outbreak, a dynamic which further elongates a return to higher occupancy levels.  THere is not a large number of individual LTC cases, but the constant media focus on COVID cases gives pause to some who would be considering moving a family member into an LTC or retirement home  

In general, the price action in the backdrop of these factors isn't surprising.  I believe the dividend is sustainable and a number of these factors are transitory.  HOwever, legislation changes need to be watched closely, in addition to any changes made to the historical funding of new builds, where the governmental subsidies make the economics very appealing for operators (and a big reason why I invested in Sienna in the first place).  

GLTA.