NEW YORK ( TheStreet) -- F5 Networks ( FFIV), one of last year's high-flying technology stocks, plunged yesterday after first-quarter revenue and a sales forecast for the current quarter missed analysts' estimates.Mark Schultz, manager of the MTB Mid-Cap Growth Fund ( AMCRX), says F5 investors ought to take advantage of the decline and "reload." The mutual fund, which garners three of five stars from fund-tracking firm Morningstar ( MORN), has returned 29% over the past year, better than 87% of its peers. Over five years, the MTB Mid-Cap Growth Fund has returned an average of 6% annually, outperforming 76% of its Morningstar rivals. Welcome to TheStreet.com's Fund Manager Five Spot, where America's top mutual fund managers give their best stock picks and views on the market in a five-question format. You've held F5 Networks a long time. Shares of the company, which makes software to manage computer networks, slid yesterday, dragging down Citrix Systems (CTXS) and Riverbed Technology (RVBD). Are you sticking with it? Schultz: The company has very strong secular drivers behind it. It is taking share from competitors like Cisco ( CSCO) and that's a very important validation of the quality of their product. And we see this network-management feature becoming even more important as networks try to manage the priority of traffic. The stock had a pullback on quarterly earnings, but we think this gives investors an opportunity to reload. What may keep mid-cap stocks in the market's sweet spot in the coming year? Schultz: I've seen research that they have been in the so-called sweet spot for the past 70 years in the U.S. The reason is that they offer investors a compelling menu of companies in which to invest. They have prudent business models and they are beyond the infancy of small caps, but they still have a lot of runway ahead of them. Green Dot Corp. (GDOT) went public in the past year. You don't normally buy companies without long track records in the fund. What is special about this name? Schultz: IPOs are not normally our specialty in the mid-cap growth fund. Usually we look for companies with longer trading histories. But we see the area of prepaid debit cards to be a very attractive one with long-term secular growth drivers behind it. The company has a strategic relationship with Wal-Mart ( WMT), which gives it access to many customers. And we see "prepaid" increasingly becoming a replacement for cash and checks. You also hold Lululemon (LULU). Will the clothing company be able to hold off competitors seeking to enter this niche? Schultz: They may provide a somewhat bigger target because they are pioneering the area of yoga-wear specifically, but also athletic-wear tailored to the ladies market. So in that respect, they are ahead of the market and the people to shoot for. We continue to like the name. It's been a multi-year holding for the fund and very successful for us.
We see them having compelling growth opportunities with square footage expansion in the U.S. and internationally, where they are just getting a toe-hold in some markets. The Web site is relatively new and is getting a lot of traction. And for the last few months, the company has faced the enviable challenge of just keeping enough inventory on the shelves. Why do you like Lufkin Industries (LUFK), which is a bit off the beaten track, in the energy sector? 4:07 Schultz: It's the leader in the market for artificial lift. As oil wells mature, they require some assistance to provide pressure to lift the oil out of the ground and get it into the pipeline. Lufkin does that better than anybody else. It faces some competition, but it's limited. And with the proliferation of new wells being drilled and also the aging of land-based production in the United States and other international markets, there are a lot of opportunities for Lufkin to pick up additional orders. -- Reported by Gregg Greenberg in New York.