Consumers may be holding on to their wallets, but health care companies are on a buying spree. Global M&A volume for the sector — including Pfizer’s $68 billion acquisition of Wyeth — rose to $128 billion in the first quarter of 2009, compared with just $18 billion in the previous quarter and $30.5 billion in the same period a year earlier. Considering that first-quarter M&A activity was down 36 percent from year-ago levels, according to Dealogic, the upsurge by drug companies is welcome news for bankers, who had their busiest spate of deal making since the fourth quarter of 1999, when health care companies made $157 billion worth of transactions. But bankers are working harder for their money these days. The 1999 benchmark was achieved with 282 deals, while the sector’s volume in the latest quarter was based on 442 deals. In today’s recessionary environment, however, few complaints are likely to be voiced.