The S & P 500 — down about 20% so far this year — is on pace for its worst first half of the year since 1970. But fund manager Robert Luna believes it could be primed for a rally. "It's definitely time for a rally talk because there's a lot of pessimism out there right now, similar to what we saw back then [in 1970 when it was] down 21%. We're very close to that," Luna told CNBC "Squawk Box Asia" on Thursday. Luna, CEO and chief investment strategist at Surevest Wealth Management, noted that around 90% of stocks on the S & P 500 are trading below their 200-day average — a key indicator used by traders and analysts to determine long-term market trends. But he believes the worst could soon be over, due to the "record amounts of money" on the sidelines, adding that it's "all a recipe ... for a market rally at some point." "I can't tell you whether or not we're going to be up 25% or 26%, but I can tell you this: if you are one of those people who have money sitting on the sidelines, if you look at where valuations are today and if you look at some of the statistics in terms of where we've been at prior to market bottoms, we do think now is time to start putting some money into this market," he said. Not everyone is convinced, however . Trevor Greetham, head of multi-asset at Royal London Asset Management, told CNBC this week: "This rally could persist a bit longer, but don't think this is the end of the bear market – I think there's quite a bit more time to run through, and you've got to be tactical and you've got to be diversified." No 'bell at the bottom' While it's rewarding to catch the bottom of a sell-off, it is notoriously difficult to do so. "There's nobody who's going to ring a bell at the bottom and say: it's time to get in now, we have finally hit a bottom," Luna said. He noted that the S & P 500 has historically traded about 30%-50% from its high in prior recessions. The index is down about 20% this year, which could mean more downside to come. Luna warned that there could be more selloffs if the Fed turns more hawkish than expected, inflation worsens or if corporates begin to turn bearish on earnings. If that happens, the S & P 500 could test the 3,250 to 3,300 level, he added. That's below its close of 3,818.83 Wednesday. But investors could utilize dollar cost averaging — a strategy that involves investing the same amount at regular intervals, regardless of what markets are doing. "I think that's really the prudent strategy right now," Luna said. Stock picks Luna believes that the technology and consumer discretionary sectors — which have been hit the hardest this year — could be "the first" to lead the economy out of the recession. One of his top picks is Disney . He says the company will be "around for a very long time," with the company's "great management" providing it with a competitive advantage. He also likes Meta — a company he thinks will continue to grow its topline by about 25%. "When you can find a company that's growing double-digits during this recession — which I believe we're either in or headed into — those are companies that you want to own," Luna said. He noted that the stock is trading at just 12x forward earnings — lower than some other tech companies — implying that "a lot of the bad news has been priced in." Forward earnings are an estimate of a company's expected earnings. When compared to its share price, the resulting ratio provides an indication of the company's valuation relative to its peers. Another stock that Luna likes is Texas-based cybersecurity firm CrowdStrike . He says the company will continue to "grow 50% to 55%" even in today's volatile environment — with cybersecurity becoming a bigger issue for companies. Starbucks also made Luna's list of top stocks. He believes China's reopening from its Covid-related lockdowns will be a "tailwind" for the company.