Blackstone is spending $325M for two apartment buildings in East Cambridge in one of Greater Boston's largest investment sales of the year.

The private equity giant, through its LivCor multifamily arm, bought 1 Leighton, a 426-unit, 22-story tower, for $281M and 10 Glassworks Ave., a 103-unit loft building behind 1 Leighton, for $44M from Avalon Bay Communities earlier this month, according to Middlesex County land records.

The neighboring luxury rental complexes sit alongside the MBTA’s Green Line and less than a mile from the Kendall Square life sciences cluster. AvalonBay didn't respond to a request for comment Tuesday. A Blackstone spokesperson declined to comment.

The sale amounts to an average of $660K per unit at 1 Leighton and $427K per unit at 10 Glassworks Ave. The transaction appears to be the largest multifamily purchase in 2021 in Greater Boston. Earlier this year, The Green Cities Co. paid $95.5M for a 295-unit community in Malden, while Berkeley Investments paid $95M for a combined 372 units in Lawrence.

1 Leighton, known as Avalon North Point, was built in 2008 by Archstone, which AvalonBay acquired in 2013. AvalonBay completed its conversion of 10 Glassworks, the former 60K SF Maple Leaf Franks hot dog factory, into lofts in 2014.

Not included in the transactions was the adjacent 2 Leighton, AvalonBay’s AVA North Point residential development.

Multifamily assets have increased in price more than any other asset class since May of last year, surpassing even industrial properties according to a Real Capital Analytics’ report released last week. Nationwide, apartment buildings rose in price 10.1% year-over-year.

Urban rents in Boston have also grown slightly after declining precipitously during the coronavirus pandemic, rising approximately 1% last month to $2,200 on average for a one-bedroom, according to Zumper. Boston remains among the priciest rental markets in the nation, rising last month to third behind New York City and San Francisco, according to the report. Studios at 1 Leighton start at $2,540 and one-bedrooms at $2,960, according to AvalonBay's website.