The value for Institutional Holdings Percentage or instituteholdingspct can be higher than 100 percent as the number of shares counted belong to different portfolio dates that can cause a double counting of shares. 

The methodology used to calculate institutehodlingspct is: 

We search the portfolio with the closest portfolio date before the calculation as of date within a time range and use it in our ownership calculation. Below is the search time range for each type

Mutual Fund - 9 Months
13F - 6 Months
ScheduleD - 15 months
Mutual Fund Aggregate - 15 months

The longer the distance between the portfolio date and the as of date, the more likely the double counting of shares happens.

Based on this methodology we are unable to avoid double counting of shares and percentage ownership over 100 in the owner summaries calculation.