Citicorp CEO Vikram Pandit got a slap in the face last month when shareholders of the global financial conglomerate rejected his proposed $14.9m pay package. While the vote isn't binding on the Citicorp board, it certainly was a wake-up call. And it shows the boardrooms that shareholders won't put up any more with mad mega-bucks going to under-performing execs – and doing something about it.

No rewards for failure

Suddenly, shareholder rebellions are fashionable. Shareholders at Goldman Sachs, Bank of America and other big corporations have been registering their displeasure at the largesse being lavished on their executives.

The revolt is taking shape in Europe, too. The board at the London-based mega-bank Barclays recently apologised to shareholders after they pushed back against CEO Bob Diamond's eye-popping £17.7m compensation package. Andrew Moss, head of Aviva, Britain's largest insurer, resigned after shareholders rejected his pay package. Proposed pay deals have been challenged at Credit Suisse bank and several firms in the Netherlands.

Some of these companies have been the target of protests from Occupy-inspired groups who question the fairness of lavish executive pay.

But the shareholder revolts are about disappointing performance, too. With share prices and return on equity slumping, financial consultant Tim Bush told the BBC that Diamond's proposed payout was, quite simply, "a reward for failure".

A sign of things to come?

Is this the start of something big? Mark Gongloff at the Huffington Post is not convinced. "Shareholders actually have little in common with Occupy Wall Street protesters," he writes. "Except in fairly extraordinary circumstances, they don't much care about how much people get paid, as long as earnings and share prices keep rising... Last year, only 36 of 2,225 companies said shareholders voted down their compensation plans."

But Robert Reich, US labour secretary in the Clinton administration, believes this is just the beginning. "The real news here is new-found activism among institutional investors – especially the managers of pension funds and mutual funds," he says. "Institutional investors are catching on to a truth they should have understood years ago: when executive pay goes through the roof, there’s less money left for everyone else who owns shares of the company."

Take action: Let's build on this momentum. The UK-based NGO FairPensions has an online tool to send a message to fund managers, urging them to resist spiralling bonuses at the companies they invest in.