Poker, the Pitt crew revealed the reasons in subtle ways through...

Poker, the Pitt crew revealed the reasons in subtle ways through some of their past announcements. My reading of them isn't perfect, but here's my understanding (no specific order of priority):

1. Industrial property for sale in OZ is priced higher than the Pitt crew believe are reasonable buying opportunities. They noted increased demand from offshore sources, but also increased domestic demand (others have discovered the benefits of industrial vs retail and office property). Buying ANI at the premium they paid may be better value than buying individual on-market properties currently. The drawn out takeover may have resulted in some escalation of commitment effect, but TIX seems to be good at relying on the numbers to figure out whether there is value in the acquisition.

2. The combined entity will receive more attention and demand from brokers and instos, thereby raising the share price above NTA closer to market norms. KPMG estimates an average of 10% above NTA across several AREITs, but getting on the ASX300 AREIT and hopefully eventually on other indexes will increase that premium further (GOZ -- which we have as a smaller holding -- jumped to 35% above NTA this past year due to its addition to major indexes!).
I sense the Pitt crew have been frustrated for some time by TIX's share price being little more than NTA . In late 2013, TIX did a share buyback for this reason. The buyback re-rated the stock very nicely, but for the long run TIX needs to be big enough to satisfy insto minimum size requirements or liquidity comfort levels and get broker researcher attention. (ANI had the same problem until the TIX offer emerged.)

3. I really believe the Pitt crew sees opportunities to improve the ANI asset portfolio and/or admin efficiencies, even if only slightly. Time will tell if their statements translate into results, but they did provide some evidence on this point.