WILLBROS GROUP INC DEL

CUSIP: 969203108 Class: COMMON STOCK

NISA INVESTMENT ADVISORS, LLC's Holding History (CIK: 0000937615)

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

Q3 2017
Shares 3,750 Value ($000) $12 Avg Close — Range —
Q2 2017
Shares 3,750 Value ($000) $9 Avg Close — Range —
Q1 2017
Shares 800 Value ($000) $2 Avg Close — Range —
Q4 2016
Shares 1,500 Value ($000) $5 Avg Close — Range —