Their move follows an activist campaign by hedge fund Starboard Value LP, which is pushing Yahoo to consider a deal with AOL and unlock Yahoo's valuable stakes in Asian Web companies.
Armstrong has been receptive to these Yahoo shareholders and acknowledged the potential benefits of a deal, the Yahoo investors said.
But he has downplayed the possibility of a transaction, according to the investors and two sources close to AOL.
There are no talks between the two companies and Armstrong has indicated he would only consider a friendly deal, the investors said.
AOL and Yahoo declined to comment. The total holdings of the Yahoo shareholders who had made overtures to Armstrong could not be determined.
Two top-10 AOL investors said that they also met with Armstrong in recent weeks to discuss the possibility of a deal with Yahoo.
These shareholders were left with the impression that a combined company could yield as much as $1.5 billion in cost savings.
Starboard, which did not speak to Reuters, wants Yahoo to spin off its Web and email business, merging them into AOL, one Yahoo investor who has spoken with the activist said.
That would leave Yahoo’s holdings in Chinese e-commerce giant Alibaba Group Holding Ltd and Yahoo Japan Corp in a separate company, satisfying investors who want the company to monetise those assets.
Starboard was once active in AOL and lost a 2012 battle to unseat three board directors.
Yahoo’s market value is about $47 billion, while its Alibaba stake alone is worth $44 billion, meaning the current Yahoo share price reflects little value to the core business.
Some of the investors see the email, Web site and other operations worth as much as $7 billion.
Armstrong, a former Google executive who has been at the helm at AOL since 2009, is credited with reviving a dying brand, helped by a set of purchases including Adap.TV, an automated video advertising platform.