Typically, securities law deals with shark repellents, convertible bonds as anti takeover defenses. But strategic licensing of trademarks and brand names can serve the purpose even more effectively-specially in consumer goods and other IPR intensive sectors. Generally, the holding company licenses brands to subsidiaries perpetually with option to terminate if change of management happens. The termination clause for change in control is standard but it is the perpetual licensing which distinguishes a 'takeover pill" from a genuine transaction.
For example, R&T's clause reads "The Agreement grants an exclusive and perpetual license to use the „Reid & Taylor‟ trademark in India and other territories specified in the Agreement. The Agreement shall continue in perpetuity unless .....it is terminated by either party for reasons such as liquidation, change of management ....".
Tata's clause is much more restrictive(no perpetual) but then it has much more at stake so that is understandable.
Takeaway:-Before investing in a company hoping for M&A takeover battles, check out the IPR assets and how they are structured for the company