Thomas H. Lee Partners has closed its sixth and largest-ever fund at $8.1 billion, two people briefed on the firm’s plans told DealBook, amid the new credit landscape that is less hospitable to mega-deals like that for Clear Channel Communications.

The fund, Thomas H. Lee Equity Partners VI, closed in October, these people said. THL Partners, which is based in Boston and owns companies like Dunkin’ Brands and the Warner Music Group, also raised $2 billion for co-investment vehicles for the fund.

A spokeswoman for the firm declined to comment.

Private equity firms rely on access to cheap debt for their deal making. But since the credit markets’ spasms this summer, that financing has largely dried up, leaving those firms unable to strike deals as large as they had earlier this year.

Though the firm’s closing of its fund might seem like a vote of confidence in private equity’s prospects, that seems less the case upon closer examination.

For one, THL’s new fund is not largest ever; the Blackstone Group announced in August that it had raised a $21.7 billion fund, edging out Goldman Sachs for that honor.

Nor did the firm raise all that money this fall. The fund opened last year, and a large portion of its capital has already been apportioned to several buyouts. Among these deals are the buyouts of Clear Channel; Univision Communications, the largest Spanish-language media company in the United States; and Ceridian, a human resources company. (Blackstone’s latest fund similarly closed after an extended fundraising period.)

The $12 billion Univision deal, in which Thomas H. Lee was a member of a consortium, closed last year. The $5.3 Ceridian deal, which was made with the insurer Fidelity National Financial, closed last month. The nearly $20 billion Clear Channel deal, made with Bain Capital, is scheduled to close early next year.