The S&P/ASX 200 Index (ASX: XJO) finished up 3.8% in May, with some ASX 200 shares charging ahead of those gains and others lagging well behind.

Yesterday we covered five of the month's top performers.

Today, we profile five of the biggest laggards.

Now, do take note that just because a stock has had a bad month doesn't mean it can't come roaring back. Any more than a stock which has had a banner month can't be in for a rough patch ahead.

With that said, here are five ASX 200 shares that took a steep fall in the month just past.

ASX 200 shares catching headwinds in May

The first ASX 200 share that lost a lot of ground in May is Insignia Financial Ltd (ASX: IFL).

Shares in the financial services company closed out April trading for $3.79 and finished May at $3.36 apiece. That saw the Insignia Financial share price down 11.4% over the month.

That loss, and then some, can be attributed to 14 May. Insignia shares closed down 15.8% on the day after the company reported that Bain Capital was not going forward with its acquisition proposal. Insignia said it remains hopeful that a similarly priced takeover offer ($5.00 per share) from CC Capital Partners will proceed.

The second ASX 200 share best avoided in May was IDP Education Ltd (ASX: IEL).

Shares in the language testing and student placement provider ended April at $8.86 and closed out May trading for $7.80. This saw the IDP Education share price down 12.0% over the month.

IDP has been struggling amid increasingly restrictive policies on foreign student enrolments in its core markets of the United Kingdom, the United States, Canada, and Australia. Policy uncertainty in those nations remains a concern for investors heading into June.

Which brings us to the third ASX 200 share that took a big tumble in May, Pilbara Minerals Ltd (ASX: PLS).

Shares in the Aussie lithium miner closed April at $1.51 and closed May trading for $1.24 each. That puts the Pilbara Minerals share price down 17.9% for the month.

There was no fresh news out from Pilbara over the month, with most of the selling pressure likely driven by a roughly 10% decline in lithium prices over the month.

Moving on to the fourth ASX 200 share that took a beating in May, we have Nufarm Ltd (ASX: NUF).

Shares in the agricultural chemical and seed technology company closed April at $3.85 and finished May at $2.38 apiece. This saw the Nufarm share price down a precipitous 38.2% in May.

The Nufarm share price closed down 30.1% on 21 May following the release of the company's half-year results. Investors were hitting their sell buttons after Nufarm reported a 39% year-on-year decline in statutory net profit after tax to $29.8 million for the half. Underlying net profit after tax was down 24% to $38.5 million.

Leading the way down

Rounding off with the ASX 200 share posting the biggest loss in May, we turn to Healius Ltd (ASX: HLS).

Shares in the pathology and imaging provider finished April at $1.46 and closed out May trading for 88 cents apiece. That puts the Healius share price down 39.7% for the month.

But Healius investors won't have felt nearly as much of that loss as that figure suggests.

That's because the ASX 200 share paid a whopping 41.3 cents per share fully franked special dividend on 23 May. And much of the retrace in the share price was due to the stock trading ex-dividend on 9 May, when shares closed down 25.0% for the day.

So, if we add that 41.3 cents per share dividend back into the closing price at the end of May, we get an adjusted closing price of $1.293 per share. Which means investors holding the stock for the entire month will have realised a significantly lesser loss of 11.5%.