For ownCloud installations on example.com/owncloud instead of a own subdomain.

owncloudInSubdirectory.conf

location /owncloud/ {
	error_page 403 = /owncloud/core/templates/403.php;
	error_page 404 = /owncloud/core/templates/404.php;

	client_max_body_size 0;
	proxy_buffering off;

	rewrite ^/owncloud/caldav(.*)$ /owncloud/remote.php/caldav$1 redirect;
	rewrite ^/owncloud/carddav(.*)$ /owncloud/remote.php/carddav$1 redirect;
	rewrite ^/owncloud/webdav(.*)$ /owncloud/remote.php/webdav$1 redirect;

	# The following 2 rules are only needed with webfinger
	rewrite ^/owncloud/.well-known/host-meta /owncloud/public.php?service=host-meta break;
	rewrite ^/owncloud/.well-known/host-meta.json /owncloud/public.php?service=host-meta-json break;

	rewrite ^/owncloud/.well-known/carddav /owncloud/remote.php/carddav/ redirect;
	rewrite ^/owncloud/.well-known/caldav /owncloud/remote.php/caldav/ redirect;

	rewrite ^/owncloud(/core/doc/[^\/]+/)$ /owncloud$1/index.html;

	try_files $uri $uri/ index.php;

	location ~ ^/owncloud/(?:\.htaccess|data|config|db_structure\.xml|README) {
		deny all;
	}

	location ~ \.php(?:$|/) {
		fastcgi_buffers 64 4K;
		fastcgi_split_path_info ^(.+\.php)(/.+)$;
		include /etc/nginx/fastcgi_params;
		fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
		fastcgi_param PATH_INFO $fastcgi_path_info;
		fastcgi_param HTTPS on;
		fastcgi_pass unix:/var/lib/php5-fpm/web.sock;
	}

	# Optional: set long EXPIRES header on static assets
	location ~* \.(?:jpg|jpeg|gif|bmp|ico|png|css|js|swf)$ {
		expires 30d;
		access_log off;
	}
}