The workers' union at Samsung Electronics has threatened an 18-day strike from May 21 if management doesn't meet it demands for bonus pay.

Samsung Electronics' stock lost as much as $66 billion in market cap earlier today when it was reported that no agreement was reached after talks between the management and the union.

Samsung's shares have been reaching new heights recently as the company enjoys a surge of investor interest on the back of superb earnings for its semiconductor division.

Over 41,000 workers would go on strike if an agreement is not reached by May 21. The union is demanding 15% of Samsung Electronics' operating profit as performance bonus in addition to removal of caps on bonus payments as well as formalization of the bonus structure.

The management has reportedly offered to allocate 10% of operating profits to bonus payments as well as a one-time special compensation package.

The stock came down over 6% today, before gradually recovering and turning positive. The change in sentiment was driven by remarks from South Korean government officials regarding “active assistance” being provided to avoid a strike.

The union had previously gone on a single-shift strike on April 23 which it said led to a 58% drop in foundry and 18% drop in memory production for that day. The union estimates that an 18-day strike would cost Samsung some $20 billion.

Samsung would hope that it doesn't come to that, as the consequences would be felt industry-wide. The company is critical to the global memory supply and any disruption in chip production would deliver a supply shock that's best avoided.