I've been told it was RBS placing a Macquarie Insto holding back to retail holders.
I've checked the top50 and that is definately feasible = early in march they were #3 with just under 5m shares.
I asked the qu "why are they selling out just before a major transaction?" and was told they use their holdings to get work raising debt for various companies - not as an investment... ie its a kind of a sales generation tool for the macquarie guys or a marketing slush fund... and given that TXN will not need debt they want to redeploy the funds to another potential client.
I remain skeptical ... but as I don't know any of the Macquarie guys to check I can't contradict it.
TXN Price at posting:
66.0¢ Sentiment: Buy Disclosure: Held