Figures released ahead of the school's Global Leadership Summit also suggest 40% are already planning their next career move when they start a new role.
Richard Hytner, LBS adjunct associate professor of marketing, told HR magazine employers need to "wake up" if they hope to attract and retain the high-potential workers of this generation.
"It's not enough to simply offer them higher compensation any more," he said. "Employers need to put aside their own biases and prejudices about what makes a great career and realise what they valued when they started out is absolutely not the same as what the new generation value.
"This isn't just about young people's attitude to work, there is a genuine shift in their values."
Hytner said that companies in the UK have a real problem communicating their values and purpose to employees and external customers.
"If even the people working for you don't know what your values are, how can you hope to get the message across to anyone else?" he said.
KFC organisational development director Karen Ancira told HR magazine keeping "up to speed" with the main drivers of Gen Y employees, as well as offering development, is the key to retention.
"They value genuine opportunities for new roles and clear career paths perhaps more than previous generations," she said.
"We want our younger employees to see that we listen to them and have a true open door policy. These are some of the things that are most important to them."
