diff --git a/app/lib/formatter.rb b/app/lib/formatter.rb
index 2611bcbae01..f13b183ad2c 100644
--- a/app/lib/formatter.rb
+++ b/app/lib/formatter.rb
@@ -85,7 +85,7 @@ class Formatter
   end
 
   def format_field(account, str, **options)
-    html = account.local? ? encode_and_link_urls(str, me: true) : reformat(str)
+    html = account.local? ? encode_and_link_urls(str, me: true, with_domain: true) : reformat(str)
     html = encode_custom_emojis(html, account.emojis, options[:autoplay]) if options[:custom_emojify]
     html.html_safe # rubocop:disable Rails/OutputSafety
   end
@@ -122,7 +122,7 @@ class Formatter
       elsif entity[:hashtag]
         link_to_hashtag(entity)
       elsif entity[:screen_name]
-        link_to_mention(entity, accounts)
+        link_to_mention(entity, accounts, options)
       end
     end
   end
@@ -264,22 +264,37 @@ class Formatter
     encode(entity[:url])
   end
 
-  def link_to_mention(entity, linkable_accounts)
+  def link_to_mention(entity, linkable_accounts, options = {})
     acct = entity[:screen_name]
 
-    return link_to_account(acct) unless linkable_accounts
+    return link_to_account(acct, options) unless linkable_accounts
 
-    account = linkable_accounts.find { |item| TagManager.instance.same_acct?(item.acct, acct) }
-    account ? mention_html(account) : "@#{encode(acct)}"
+    same_username_hits = 0
+    account = nil
+    username, domain = acct.split('@')
+    domain = nil if TagManager.instance.local_domain?(domain)
+
+    linkable_accounts.each do |item|
+      same_username = item.username.casecmp(username).zero?
+      same_domain   = item.domain.nil? ? domain.nil? : item.domain.casecmp(domain).zero?
+
+      if same_username && !same_domain
+        same_username_hits += 1
+      elsif same_username && same_domain
+        account = item
+      end
+    end
+
+    account ? mention_html(account, with_domain: same_username_hits.positive? || options[:with_domain]) : "@#{encode(acct)}"
   end
 
-  def link_to_account(acct)
+  def link_to_account(acct, options = {})
     username, domain = acct.split('@')
 
     domain  = nil if TagManager.instance.local_domain?(domain)
     account = EntityCache.instance.mention(username, domain)
 
-    account ? mention_html(account) : "@#{encode(acct)}"
+    account ? mention_html(account, with_domain: options[:with_domain]) : "@#{encode(acct)}"
   end
 
   def link_to_hashtag(entity)
@@ -300,7 +315,7 @@ class Formatter
     "<a href=\"#{encode(tag_url(tag))}\" class=\"mention hashtag\" rel=\"tag\">#<span>#{encode(tag)}</span></a>"
   end
 
-  def mention_html(account)
-    "<span class=\"h-card\"><a href=\"#{encode(ActivityPub::TagManager.instance.url_for(account))}\" class=\"u-url mention\">@<span>#{encode(account.username)}</span></a></span>"
+  def mention_html(account, with_domain: false)
+    "<span class=\"h-card\"><a href=\"#{encode(ActivityPub::TagManager.instance.url_for(account))}\" class=\"u-url mention\">@<span>#{encode(with_domain ? account.pretty_acct : account.username)}</span></a></span>"
   end
 end
diff --git a/app/lib/tag_manager.rb b/app/lib/tag_manager.rb
index c88cf499474..39a98c3eb92 100644
--- a/app/lib/tag_manager.rb
+++ b/app/lib/tag_manager.rb
@@ -22,14 +22,6 @@ class TagManager
     uri.normalized_host
   end
 
-  def same_acct?(canonical, needle)
-    return true if canonical.casecmp(needle).zero?
-
-    username, domain = needle.split('@')
-
-    local_domain?(domain) && canonical.casecmp(username).zero?
-  end
-
   def local_url?(url)
     uri    = Addressable::URI.parse(url).normalize
     domain = uri.host + (uri.port ? ":#{uri.port}" : '')
diff --git a/spec/lib/tag_manager_spec.rb b/spec/lib/tag_manager_spec.rb
index e9a7aa93441..2230f971037 100644
--- a/spec/lib/tag_manager_spec.rb
+++ b/spec/lib/tag_manager_spec.rb
@@ -83,40 +83,4 @@ RSpec.describe TagManager do
       expect(TagManager.instance.local_url?('https://domainn.test/')).to eq false
     end
   end
-
-  describe '#same_acct?' do
-    # The following comparisons MUST be case-insensitive.
-
-    it 'returns true if the needle has a correct username and domain for remote user' do
-      expect(TagManager.instance.same_acct?('username@domain.test', 'UsErNaMe@DoMaIn.Test')).to eq true
-    end
-
-    it 'returns false if the needle is missing a domain for remote user' do
-      expect(TagManager.instance.same_acct?('username@domain.test', 'UsErNaMe')).to eq false
-    end
-
-    it 'returns false if the needle has an incorrect domain for remote user' do
-      expect(TagManager.instance.same_acct?('username@domain.test', 'UsErNaMe@incorrect.test')).to eq false
-    end
-
-    it 'returns false if the needle has an incorrect username for remote user' do
-      expect(TagManager.instance.same_acct?('username@domain.test', 'incorrect@DoMaIn.test')).to eq false
-    end
-
-    it 'returns true if the needle has a correct username and domain for local user' do
-      expect(TagManager.instance.same_acct?('username', 'UsErNaMe@Cb6E6126.nGrOk.Io')).to eq true
-    end
-
-    it 'returns true if the needle is missing a domain for local user' do
-      expect(TagManager.instance.same_acct?('username', 'UsErNaMe')).to eq true
-    end
-
-    it 'returns false if the needle has an incorrect username for local user' do
-      expect(TagManager.instance.same_acct?('username', 'UsErNaM@Cb6E6126.nGrOk.Io')).to eq false
-    end
-
-    it 'returns false if the needle has an incorrect domain for local user' do
-      expect(TagManager.instance.same_acct?('username', 'incorrect@Cb6E6126.nGrOk.Io')).to eq false
-    end
-  end
 end