IMMUNOGEN INC

CUSIP: 45253H101 Class: Common Stock

MASON STREET ADVISORS, LLC's Holding History (CIK: 0001167711)

Note: Option positions (PUT/CALL) are excluded.

Q3 2014
Shares 154,800 Value ($000) $1,639 Avg Close — Range —
Q2 2014
Shares 154,800 Value ($000) $1,834 Avg Close — Range —
Q1 2014
Shares 154,800 Value ($000) $2,311 Avg Close — Range —
Q4 2013
Shares 154,800 Value ($000) $2,271 Avg Close — Range —
Q3 2013
Shares 154,800 Value ($000) $2,635 Avg Close — Range —