The sale, analysts said at the time, highlighted the untapped value of the rest of the firm, even as it was losing a rail business that made more than 40 per cent of its profits.
What’s left over at Invensys is its Controls division, which makes dials and sensors for central heating and fridges, and Operations Management, which deals in software, measuring equipment and corporate safety.
This second unit has contracts ranging from safety protocols at Chinese nuclear power stations to Middle Eastern oil projects, and its pipeline of work shows few signs of slowing.
What’s no longer left over is the £490m pension fund hole, which Invensys is paying down using the windfall from the Rail sale.
With the Rail transaction cleared by competition bodies and nearing completion, ValueAct’s stake-building comes at just the right time to draw fresh attention to Invensys’s credentials as a takeover target.
The US hedge fund’s other investments, ranging from Microsoft to ratings agency Moody’s, are generally made to push for change to improve returns.
But its joint takeover bid for Misys last year alongside CVC Capital Partners shows that it will also take a tilt at a company if it sees enough value locked away – as the market seems to already see in Invensys.
Also among possible bidders would be Emerson, which started and then dropped talks with Invensys last summer after it recoiled from the firm’s now-funded pension scheme.
Another contender could be Honeywell, the Fortune 100 industrial company that has been on the acquisition trail for the last year or so and reported a cash pile of $4.5bn in its quarterly results earlier this month.
Invensys’s share price has climbed 16 per cent since its November jolt, which some analysts reckon prices in a takeover. But investors are unlikely to have seen the peak of the bid buzz yet.