Last month I took a family vacation to Charleston, South Carolina less than a week after Hurricane Irma raked The Holy City with heavy rain and high winds. Except for a few downed trees and some beach erosion, it was difficult to tell anything happened. The residents of Charleston have experience dealing with a storm of this magnitude and started cleaning up before it was over.

By the time we checked into to our beach house the sun was shining and the streets were teeming with tourists. In a similar fashion, the S&P 500 Index dropped 1% during the first week of September when the financial damage from hurricanes Harvey and Irma was still unknown. But once it became clear that only the energy sector suffered anything more than a glancing blow the stock market roared back to life.

Against that volatile backdrop, our portfolio performed pretty well. The six holdings that were in the portfolio for the entire month recorded an average gain of 3.7%, more than double the 1.5% return on the index. Including the one stock that we sold and the two that we added during the month, our portfolio recorded a weighted-average gain of 2.5% based on the number of days held for each position.

Our biggest winner for the month was Bank of the Ozarks (OZRK), which jumped 10.8% last month after taking a big drop in early August. There was a lot of speculation that the sudden resignation of the bank’s chief lending officer in late August meant bad news was on the way. But since then nothing has happened to confirm those fears, and next week’s third-quarter earnings report should put them to rest once and for all.

Our second biggest winner, KLA-Tencor (KLAC), was in the portfolio for only two weeks but has already racked up an 8.2% gain. I wish I could tell you why, but other than a routine press release three weeks ago there has been no news out of the company to explain it. The average daily trading volume has been a little more than normal since then, but not high enough to indicate a major buying initiative from an institutional investor.

Our third stock taking a big jump last month was Fox Factory Holding (FOXF), up 7.8% despite no news of any sort out of the company. For that reason, I raised the stop price for FOXF to $42 last week to lock in most of our targeted gain. Small cap stocks like FOXF have taken off recently over the anticipation of a major corporate income tax reduction, but that is far from being a done deal.

Also helping us beat the index average was Bojangles (BOJA), up 2.6% for the month despite dipping during the first week of September. Investors feared that Hurricane Harvey threatened its core markets in North and South Carolina that house more than half of its restaurants. Once again there was no specific news to explain its recent rise, but the company has confirmed that it is well on its way to executing the corporate strategy it laid out in an Investor Presentation at the start of the year.

Similar to Bojangles, shares of Bank of New York Mellon (BK) began September on a down note before rallying strongly to end it with a 1.4% net gain. The stock came under selling pressure in early August when famed activist investor Nelson Peltz of Trian Fund Management unloaded a third of his holdings in BK, but since then it has bounced back. The company is due to release its next earnings report on October 19, a week before our target holding period is due to expire.

Following a similar trading pattern last month was Athene Holdings (ATH), which plunged 9% during the first week of September before recovering to eke out a 0.9% improvement over its closing price in August. That timing coincides with an Investor Presentation the company made at the Barclays Global Financial Services Conference that resulted in several analysts revising their one-year price for ATH upward.

Although we only held Australian mining company BHP Billiton (BHP) in our portfolio for one day in September, it contributed a 0.3% gain. As explained in the buy alert issued last week, BHP’s operating results should show continuing improvement as it focuses on its core business. For that reason, I’m expecting a bump in its share price following the release of its third-quarter results on October 18.

We lost ground in Western Digital (WDC) last month, which backtracked 1.2% after Toshiba rejected the company’s bid to acquire its flash memory unit. Western Digital isn’t giving up without a fight, but at this point it appears that deal isn’t going to happen. I believe the selling in reaction to this turn of events is overdone, and I expect WDC to rally after releasing quarterly results at the end of this month. Speculators may want to take a look at the November call options.

We sold United Therapeutics (UTHR) on September 20 at a 9% loss after it closed beneath our stop price of $118. Oddly, the stock sagged after its Independent Data Monitoring Committee recommended continuing with the stage-3 trial for Orenitram. Normally biotech stocks suffer when a stage-3 trial ends prematurely, so the stock’s sudden weakness is difficult to fathom. Nevertheless, we recognize the stock market’s ability to move unpredictably like a hurricane, sometimes unexplainable but always undeniable.