PNC Financial Services Group wants to sell its stake in BlackRock, the world's largest asset manager, a deal that could fetch about $12 billion.

PNC's chairman and chief executive, Bill Demchak, said it's the "worst-kept secret on Wall Street" that the Pittsburgh company has been looking to dispose of its 21.2 % stake in BlackRock. The holding was valued at about $11.9 billion as of Wednesday.

PNC has not yet been able to reach an agreement on either selling or spinning off the BlackRock investment, largely because of tax complications, Demchak said. Demchak made the comments on Wednesday at the Barclays Global Financial Services Conference in New York.

PNC has previously explored a sale of its BlackRock stake in a tax-efficient way, a bank spokesman said Wednesday. Rick Johnson, PNC's former chief financial officer, in 2013 said BlackRock would consider selling the stake.

The $361 billion-asset PNC, which has owned a stake in the New York money manager since 1995, is the largest BlackRock shareholder. BlackRock has more than $4 trillion in assets under management.

Demchak and Thomas O'Brien, PNC's former CEO, are both BlackRock directors and PNC's general counsel, Gregory Jordan, is an official nonvoting observer to BlackRock board meetings. BlackRock also provides investment advisory, administrative and risk management services to PNC.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.