This article originally appeared in the Bangkok Post .

Each week brings with it news of the latest multi-business public company looking to ignite shareholder returns by separating. Sometimes compelled by external pressure from activist investment funds, spinoffs are taking place across a range of industries. HP Inc and Hewlett-Packard Enterprise, eBay and PayPal are among the most recent examples, and the list keeps growing.

Corporate break-ups may be in vogue, but are they worth it? Separations are costly; one-time costs typically amount to 1% to 2% of revenue, sometimes more for the most complex separations. They're time-consuming, too, generally taking 12 to 18 months from decision to close. As anyone who has embarked on a separation can attest, they're also resource-intensive and distracting for an organisation, causing a high degree of inward focus.

The big question for boards and CEOs pondering such a move is, "Does the break-up succeed in creating shareholder value?" The answer is, "sometimes". We determined this by analysing the performance 18 months post-separation of 40 transactions involving companies valued at more than US$1 billion in the 2001 to 2010 time frame. We focused on deals in which two separate public companies were formed out of a portfolio in which there had been some level of strategic and operational integration.

Based on our analysis, the top third of separations delivered significant value: The combined market cap of the new businesses after separation exceeded their pre-spin value by more than 50%. That's the good news. But in another one-third of the cases, the combined market cap of the new companies was 40% less than their pre-spin value 18 months after separating.

Read the full article in the Bangkok Post.

Andy Pasternak is a partner with Bain & Company's Chicago office, Jim Wininger is a partner with Bain's Atlanta office, and Satish Shankar is a partner with Bain's Singapore office.