diff --git a/DESCRIPTION b/DESCRIPTION
index 2e8f86b..a039370 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: statnet.common
-Version: 4.10.0-439
-Date: 2023-12-18
+Version: 4.10.0-441
+Date: 2024-01-30
 Title: Common R Scripts and Utilities Used by the Statnet Project Software
 Authors@R: c(
     person(c("Pavel", "N."), "Krivitsky", role=c("aut","cre"), email="pavel@statnet.org", comment=c(ORCID="0000-0002-9101-3362", affiliation="University of New South Wales")),
diff --git a/NAMESPACE b/NAMESPACE
index ffb7833..2f76992 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -138,6 +138,7 @@ export(ult)
 export(unused_dots_warning)
 export(unwhich)
 export(update_snctrl)
+export(var.mcmc.list)
 export(vector.namesmatch)
 export(xAxT)
 export(xTAx)
diff --git a/R/mcmc-utils.R b/R/mcmc-utils.R
index b0308c2..d40075b 100644
--- a/R/mcmc-utils.R
+++ b/R/mcmc-utils.R
@@ -10,7 +10,7 @@
 #' @name mcmc-utilities
 #' @title Utility operations for [`mcmc.list`] objects
 #' 
-#' @description \code{colMeans.mcmc.list} is a "method" for (non-generic) [`colMeans`] applicable to [`mcmc.list`] objects.
+#' @description \code{colMeans.mcmc.list} is a "method" for (non-generic) [colMeans()] applicable to [`mcmc.list`] objects.
 #' 
 #' @param x a \code{\link{mcmc.list}} object.
 #' @param \dots additional arguments to \code{\link{colMeans}} or
@@ -18,7 +18,7 @@
 #' @return \code{colMeans.mcmc} returns a vector with length equal to
 #'   the number of mcmc chains in \code{x} with the mean value for
 #'   each chain.
-#' @seealso [`colMeans`], [`mcmc.list`]
+#' @seealso [colMeans()], [`mcmc.list`]
 #' @examples
 #' data(line, package="coda")
 #' summary(line) # coda
@@ -29,15 +29,41 @@
 #' @export colMeans.mcmc.list
 colMeans.mcmc.list<-function(x,...) colMeans(as.matrix(x),...)
 
+#' @rdname mcmc-utilities
+#'
+#' @description \code{var.mcmc.list} is a "method" for (non-generic)
+#'   [var()] applicable to [`mcmc.list`] objects. Since MCMC chains
+#'   are assumed to all be sampling from the same underlying
+#'   distribution, pooled mean is used. This implementation should be
+#'   equivalent (within numerical error) to `var(as.matrix(x))` while
+#'   avoiding constructing the large matrix.
+#'
+#' @seealso [var()]
+#' @examples
+#' data(line, package="coda")
+#' var(as.matrix(line)) # coda
+#' var.mcmc.list(line) # "Method"
+#' \dontshow{
+#' stopifnot(isTRUE(all.equal(var.mcmc.list(line), var(as.matrix(line)))))
+#' }
+#' @export var.mcmc.list
+var.mcmc.list <- function(x, ...){
+  nchain <- length(x)
+  niter <- NROW(x[[1]])
+  SSW <- Reduce(`+`, lapply(x, cov)) * (niter-1)
+  SSB <- cov(t(sapply(x, colMeans))) * niter
+  (SSW+SSB) / (niter*nchain-1)
+}
+
 #' @rdname mcmc-utilities
 #'
 #' @description \code{sweep.mcmc.list} is a "method" for (non-generic)
-#'   [`sweep`] applicable to [`mcmc.list`] objects.
+#'   [sweep()] applicable to [`mcmc.list`] objects.
 #' 
-#' @param STATS,FUN,check.margin See help for [`sweep`].
+#' @param STATS,FUN,check.margin See help for [sweep()].
 #' @return \code{sweep.mcmc.list} returns an appropriately modified
 #'   version of \code{x}
-#' @seealso [`sweep`]
+#' @seealso [sweep()]
 #' @examples
 #' data(line, package="coda")
 #' colMeans.mcmc.list(line)-1:3
@@ -56,12 +82,12 @@ sweep.mcmc.list<-function(x, STATS, FUN="-", check.margin=TRUE, ...){
 #' @rdname mcmc-utilities
 #'
 #' @description \code{lapply.mcmc.list} is a "method" for (non-generic)
-#'   [`lapply`] applicable to [`mcmc.list`] objects.
+#'   [lapply()] applicable to [`mcmc.list`] objects.
 #' 
 #' @param X An [`mcmc.list`] object.
 #' @return `lapply.mcmc.list` returns an [`mcmc.list`] each of
 #'   whose chains had been passed through `FUN`.
-#' @seealso [`lapply`]
+#' @seealso [lapply()]
 #' @examples
 #' data(line, package="coda")
 #' colMeans.mcmc.list(line)[c(2,3,1)]
diff --git a/man/mcmc-utilities.Rd b/man/mcmc-utilities.Rd
index 2e11603..55deec3 100644
--- a/man/mcmc-utilities.Rd
+++ b/man/mcmc-utilities.Rd
@@ -3,12 +3,15 @@
 \name{mcmc-utilities}
 \alias{mcmc-utilities}
 \alias{colMeans.mcmc.list}
+\alias{var.mcmc.list}
 \alias{sweep.mcmc.list}
 \alias{lapply.mcmc.list}
 \title{Utility operations for \code{\link{mcmc.list}} objects}
 \usage{
 colMeans.mcmc.list(x, ...)
 
+var.mcmc.list(x, ...)
+
 sweep.mcmc.list(x, STATS, FUN = "-", check.margin = TRUE, ...)
 
 lapply.mcmc.list(X, FUN, ...)
@@ -19,7 +22,7 @@ lapply.mcmc.list(X, FUN, ...)
 \item{\dots}{additional arguments to \code{\link{colMeans}} or
 \code{\link{sweep}}.}
 
-\item{STATS, FUN, check.margin}{See help for \code{\link{sweep}}.}
+\item{STATS, FUN, check.margin}{See help for \code{\link[=sweep]{sweep()}}.}
 
 \item{X}{An \code{\link{mcmc.list}} object.}
 }
@@ -35,13 +38,20 @@ version of \code{x}
 whose chains had been passed through \code{FUN}.
 }
 \description{
-\code{colMeans.mcmc.list} is a "method" for (non-generic) \code{\link{colMeans}} applicable to \code{\link{mcmc.list}} objects.
+\code{colMeans.mcmc.list} is a "method" for (non-generic) \code{\link[=colMeans]{colMeans()}} applicable to \code{\link{mcmc.list}} objects.
+
+\code{var.mcmc.list} is a "method" for (non-generic)
+\code{\link[=var]{var()}} applicable to \code{\link{mcmc.list}} objects. Since MCMC chains
+are assumed to all be sampling from the same underlying
+distribution, pooled mean is used. This implementation should be
+equivalent (within numerical error) to \code{var(as.matrix(x))} while
+avoiding constructing the large matrix.
 
 \code{sweep.mcmc.list} is a "method" for (non-generic)
-\code{\link{sweep}} applicable to \code{\link{mcmc.list}} objects.
+\code{\link[=sweep]{sweep()}} applicable to \code{\link{mcmc.list}} objects.
 
 \code{lapply.mcmc.list} is a "method" for (non-generic)
-\code{\link{lapply}} applicable to \code{\link{mcmc.list}} objects.
+\code{\link[=lapply]{lapply()}} applicable to \code{\link{mcmc.list}} objects.
 }
 \examples{
 data(line, package="coda")
@@ -51,6 +61,12 @@ colMeans.mcmc.list(line) # "Method"
 stopifnot(isTRUE(all.equal(summary(line)$statistics[,"Mean"],colMeans.mcmc.list(line))))
 }
 data(line, package="coda")
+var(as.matrix(line)) # coda
+var.mcmc.list(line) # "Method"
+\dontshow{
+stopifnot(isTRUE(all.equal(var.mcmc.list(line), var(as.matrix(line)))))
+}
+data(line, package="coda")
 colMeans.mcmc.list(line)-1:3
 colMeans.mcmc.list(sweep.mcmc.list(line, 1:3))
 \dontshow{
@@ -64,9 +80,11 @@ stopifnot(isTRUE(all.equal(colMeans.mcmc.list(line)[c(2,3,1)],colMeans.mcmc.list
 }
 }
 \seealso{
-\code{\link{colMeans}}, \code{\link{mcmc.list}}
+\code{\link[=colMeans]{colMeans()}}, \code{\link{mcmc.list}}
+
+\code{\link[=var]{var()}}
 
-\code{\link{sweep}}
+\code{\link[=sweep]{sweep()}}
 
-\code{\link{lapply}}
+\code{\link[=lapply]{lapply()}}
 }